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Rabbit 2000 Microprocessor Designer`s Handbook

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1. 2 Device Sector Number Best Operating Vendor rei Size Size of Voltage 223 3 bytes bytes Sectors SST SST29VESI2 64K 128 512 sector 150 2 7 3 6 1 2 3 4 7 20 SST SST29EE010 128K 128 1024 sector 90 4 5 5 5 1 2 3 4 SST SST29LEO10 128K 128 1024 sector 150 3 0 3 6 11 2 3 4 All SST SST29VEOIO 128K 128 1024 sector 150 2 7 3 6 1 2 3 4 7 20 SST SST29EE020 256K 128 2048 sector 120 4 5 5 5 1 2 3 4 7 02 SST SST29LE020 256K 128 2048 sector 200 3 0 3 6 1 2 3 4 7 026 SST SST29VE020 256K 128 2048 sector 200 2 7 3 6 1 2 3 4 7 200 SST SST29SF512 64 128 512 byte 55 4 5 5 5 1 2 3 7 20 SST SST29VF512 64K 128 512 byte 55 2 7 3 6 1 2 3 7 206 SST SST29SF010 128K 128 1024 byte 55 4 5 5 5 11 2 3 720 SST SST29VF010 128K 128 1024 byte 55 2 7 3 6 1 2 3 7 206 SST SST29SF020 256K 128 2048 byte 55 4 5 5 5 11 2 3 720 SST SST29VF020 256K 128 2048 byte 55 2 7 3 6 1 2 3 7 206 SST SST29SF040 512 128 4096 byte 55 4 5 5 5 1 2 3 7 206 SST SST29VF040 512 128 4096 byte 55 2 7 3 6 1 2 3 7 206 SST SST39SF512 64 4096 16 byte 45 4 5 5 5 1 2 3 7 206 SST SST39LF512 64 4096 16 byte 45 3 0 3 6 1 2 3 7 20 SST SST39VF512 64 4096 16 byte 70 2 7 3 6 1 2 3 7 206 SST SST39SF010 128K 4096 32 byte 45 4 5 5 5 1 2 3 7 025 SST SST39LF010 128K 4096 32 byte
2. 4 2 2 Operating Voltages a ceteras d 4 2 3 Power Gonsumbption g af beta A d e i o e f 5 2 4 Through hole Technology s 5 Core Design C onipolens 7 321 CLOCKS i a a A E a 7 3 1 1 Low Power DesIgti 8 3 1 2 Conformal Coating of 32 768 kHz Oscillator Circuit 8 3 2 Basic Memory Design ss ii 9 3 2 1 Memory Access Time sinioro Da e OE RR REGE HE Red 9 3 2 2 Precautions for Unprogrammed Flash Memory ccccccceceesseseeeseeseeeseeceeseceeceseeeenseeseeeseeaes 9 3 3 PC Board Layout and Memory Line Permutation essere 11 3 4 PC Board Layout and Electromagnetic Interference 12 3 4 1 Regulations RR 12 3 4 1 1 EMI Measuring Devices sse ssensnzznnznzznninnzzonzinnzansenazzannnznnnzznnznnenenzznzzenzzazz 12 3 4 1 2 Classes For EMI Testing nennen nnne 12 3 4 2 Layout and Decoupling for Low nne nnne 13 312 T BMISSOUECeS e et ee me REFERS 13 342 2 Glock Signal Pim 14 3 4 2 3 High Frequency Oscillator Circuit esses 15 3 4 2 4 Processor Decoupling cid a a ss 17 3 4 2 5 Elimination of Power Plane sse mensenzznzanninenzennrenzanznnnzznnznnznnzzanzznzzanznnz 18
3. 29 6 1 Startup Conditions Set Up By the 1 5 nenne nre 30 6 2 BIOS Elowehatt erede HN as ae edi den S ERN EHE M TENE 31 6 3 Internally Defined Macros cccceccescessesseeseessceseeeeesecseceseeseeesecsecesecsaeeaecseeseeaecesesseseeeseseaeceeenseeeeneeeens 32 6 4 Modifying the BIOS fi ise 32 6 5 Origin Statements to the 34 6 5 1 Origin Statement Syntax n ba A a 34 6 5 2 Origin Statement Semantics sss enne nnne nter nnne nnne nnne 34 6 5 3 Origin Statement Examples eoe coiere e gg erp 36 6 5 4 Origin Directives in Program 4 eene 37 7 qu 39 74 Definition of SysIDBlock aiias niece ie pere een i ee E he ee oct i 40 EAE M 41 7 21 Reading the System ID Block vii g PR ERR CERRAR 41 7 2 2 Writing the System ID 1 000440000 0000000 41 7 3 Determining the Existence of the System ID Block esses 42 8 BIOS Support for Program 45 8 1 Overview of Cloning 2 2 is tette err P 45 8 1 1 Evolution of Cloning Support essetis 46 8 2 Creating Clone ERREUR 46 8 2 1 Steps to Enable and Set Up
4. Crystal 2400 9600 19200 57600 115200 Freq MHz baud baud baud baud baud 1 8432 23 5 2 0 3 6864 BL1800 divided by 8 47 11 5 1 0 5 5296 71 17 8 2 7 3728 BL1810 not doubled 95 23 11 3 1 9 2160 RCM2020 not doubled 119 29 14 4 11 0592 RCM2100 not doubled 143 35 17 5 2 12 9024 RCM2000 not doubled 167 41 20 6 14 7456 BL1820 doubled 191 47 23 7 3 16 5888 215 53 26 8 18 4320 TCP IP Dev Kit 239 59 29 9 4 20 2752 65 32 10 22 1184 RCM2100 doubled m 71 35 11 5 23 9616 77 38 12 25 8048 2010 doubled 83 41 13 6 27 6480 89 44 14 29 4912 BL1800 can t double 95 47 15 7 36 8640 i 119 59 19 9 44 2368 143 71 23 11 Rabbit 2000 Designer s Handbook rabbit com 67 This information is calculated with the following equation divisor crystal frequency in Hz 32 baud rate 1 If the divisor is not an integer value that baud rate is not available for that frequency identified by a in the table If the divisor is above 255 that baud rate is not available without further BIOS modification identified by in the table To allow that baud rate you need to clock the serial port desired via timer by default they run off the CPU clock 2 then scale down timer A to make the serial port divisor fall below 256 68 rabbit com Supported Rabbit 2000 Baud Rates Semiconductor Appendix B Wait State Bug B 1 Overview of the Bug A bug associated with the u
5. 21 DATASEG 30 design conventions ss eseensenzenzzonnrnzzentnzzznnznnzna 3 device identification sssssesennennnzznnznnnzznnazznnzzi 39 operating voltage 2 8 49 Rabbit 2000 Designer s Handbook rabbit com 75 origin statements 2 2 30 34 37 oscillator nnne 8 61 band ote lek 3 power consumption 4 5 regulator circuit 2 8 YDES cR 4 output enable idee ie teenies 3 20 70 P PB1 and tede e t tes 3 Pilot BIOS 2 5 anite dnt enr RAN gi 21 power consumption 2222 2 5 8 49 programming cable 3 19 62 programming connector 1 3 20 programming 19 R RC time constant sess 14 regulator Circuit i eie eei en ges 8 MOSEL l a 3 21 61 62 schetnatics 1 2 isa pe spes 7 SBGSIZE kelli iii 30 serial port 1 3 20 61 shutdown circuitry 23 sleepy 8 50 SMODE pins 20 62 30 STACK SEG e 30 standby mode oe e eenneenennnzentnnnzznnennnznnnnnznnnznnznna 8 startup delay eese ette 7 SysID block nr tienes 39 43 T Dal M 5 63 troubleshooting 61 Wall
6. Interrupts should be turned off set the interrupt level to 3 whenever writes are occurring to the flash Interrupts should not be turned back on until the write is complete an interrupt may attempt to access a function in flash while the write is occurring and fail It should not return until the write operation is finished on the chip It should return a zero in HL if the operation was successful a 3 if a timeout occurred during the wait or a 4 if an attempt was made to write over the ID block 60 rabbit com Flash Memories Semiconductor Chapter 12 Troubleshooting Tips for New Rabbit Based Systems If the Rabbit design conventions were followed and Dynamic C cannot establish target communications with the Rabbit 2000 based system there are a number of initial checks and some diagnostic tests that can help isolate the problem 12 1 Initial Checks Perform the first two checks with the RESET line pin 37 tied to ground 1 With a voltmeter check for Vpp and Ground including on the appropriate pins 2 With an oscilloscope check the 32 768 kHz oscillator on 1 pin 40 Make sure that it is oscillat ing and that the frequency is correct 3 With an oscilloscope check the main system oscillator by observing the signal CLK pin 1 With the reset held high and no existing program in the flash memory attached to the processor this signal should have a frequency one eighth of the main crystal or
7. How Dynamic Cold Boots the Target System sse 19 4 1 How the Cold Boot Mode Works In Detail sessi 20 4 2 Program Loading Process Overview isses nennen ener ener eerte 21 4 2 1 Program Loading Process Details enne 21 Rabbit Memory Or cant Zam ie 23 5 1 Physical Memory inesse teen ree i nee EUR EE RH ERR HD AED 23 Se Ll Flash IUSSIT D D EIU ILI TES 23 AE I 23 5 1 3 Basic Memory Configuration nnne nnne nne 24 2 2 Memory deg Helio E 24 5 24 Definitions eM ERIS 25 5 2 2 The Root Memory Segment nennen nnne nn nnn entere 25 5 2 2 1 Types of Code Best Suited for the Root Memory Segment 25 5 2 3 The Data Segment conico pin redet i ei ERG pa e e i iind 26 Rabbit 2000 Designer s Handbook rabbit com iii 5 24 The Stack Segment E p 26 5 2 5 The Extended Memory 26 5 3 How The Compiler Compiles to 26 5 3 1 Placement of Code in Memory nennen enne 26 5 3 2 Paged Access in Extended Memory sess 27 6 Th Rabbit BIOS
8. Rabbit 20007 Microprocessor Designer s Handbook 019 0070 070720 L The latest revision of this manual is available the Rabbit Semiconductor Web site www rabbit com for free unregistered download c B ka Rabbit 2000 Microprocessor Designer s Handbook Part Number 019 0070 070720 L Printed in U S A 2006 Rabbit Semiconductor Inc rights reserved No part of the contents of this manual may be reproduced or transmitted in any form or by any means without the express written permission of Rabbit Semiconductor Permission is granted to make one or more copies as long as the copyright page contained therein is included These copies of the manuals may not be let or sold for any reason without the express written permission of Rabbit Semiconductor Rabbit Semiconductor reserves the right to make changes and improvements to its products without providing notice Trademarks Rabbit and Dynamic C are registered trademarks of Rabbit Semiconductor 1 2 3 4 3 Semiconductor Fut US 1 1 1 Summary of Design Conventions esiti nte HO EU Fe HER 1 Rabbit Hardware Design Overview usse oda dod 3 2 1 Design Conventions 3 2 1 1 Rabbit Programming Connector E oE nennen nnne nnne nnne 3 2 12 Memory Chips ndis cab a a ari aa f a 4 21 3Os illator
9. Some macros used in the BIOS are defined internally by Dynamic C before the BIOS is compiled They are defined using tests done in the bootstrap loading or by reading variables set in the GUI These are FLASH RAM Used for conditional compilation of the BIOS to distinguish between compiling to RAM and compiling to flash These are set in the Options Compiler dialog box RAM SIZE FLASH SIZE Used to set the MMU registers and code and data sizes available to the compiler The values given by these macros represent the number of 0x1000 blocks of memory available BOARD TYPE This is read from the System ID block or defaulted to 0x100 the BL1810 JackRabbit board if no System ID block is present This can be used for conditional compilation based on board type 6 4 Modifying the BIOS The BIOS can be modified to be more specific concerning the user s configuration This can be done one step at a time making it easy to detect any problems The source code for the Universal BIOS is in BIOS RABBITBIOS C Dynamic C uses this source code for the BIOS by default but the user can specify another BIOS for Dynamic C to use in the Options Compiler dialog box There are several macros at the top of RABBITBIOS C that users may want to modify for boards they design or for special situations involving off the shelf Rabbit based boards Not all of the macros at the top of the BIOS are described here USE115KBAUD The default value of 1 specifi
10. pes Repeat File Tx Method TxMode bo T 7 Al a nce 6 All atOnce CASE er LE none Receive Cycle ko Hex ASCII Click on Help at the top left hand side of the screen for directions for using this program A diagnostic program is a group of triplets You can open the provided diagnostic programs those files with the extension diag with Dynamic C or any simple text editor if you would like to examine the triplets that are sent to the target Also serial1IO exe has the option of sending the triplets a line at a time so you can see the triplets in the one line window next to the Transmit button before they are sent NOTE Connecting the programming cable to the programming connector pulls both SMODE pins high On reset this allows a cold boot from asynchronous serial port A The reset may be applied by pushing the reset button on the target board or by checking then unchecking the box labeled when using seriallO exe In the following pages two diagnostic programs are looked at in some detail The first one is short and very simple a toggle of the status line Information regarding how to check the results of the diagnostic are given The second diagnostic program checks the processor RAM interface This example provides more detail in terms of how the triplets were derived After reading through these examples you will be able to write diagnostic program
11. 45 3 0 3 6 1 2 3 7 206 SST SST39VF010 128K 4096 32 byte 70 2 7 3 6 1 2 3 7 206 SST SST39SF020 256K 4096 64 byte 45 4 5 5 5 1 2 3 6 50 SST SST39LF020 256K 4096 64 byte 45 3 0 3 6 1 2 3 7 206 SST SST39VF020 256K 4096 64 byte 70 2 7 3 6 1 2 3 7 205 SST SST39SF040 512 4096 128 byte 45 4 5 5 5 1 2 3 7 026 SST SST39LF040 512 4096 128 byte 45 3 0 3 6 1 2 3 7 205 SST SST39VF040 512K 4096 128 byte 70 2 7 3 6 1 2 3 7 20 Winbond W29CEE011 128K 128 1024 sector 90 4 5 5 5 1 2 4 7 020 Winbond W29C020CT 256 128 2048 sector 70 4 5 5 5 1 2 4 Alls Winbond W29C040 512K 256 2048 sector 90 4 5 5 5 2 4 7 026 56 rabbit com Flash Memories Table 11 2 32 Pin Flash Memories Supported by the Rabbit 2000 Large Sector Device Sector Numb Best Operatin Device umber write Access P 3 Package Dynamic Vendor N Size Size of Mode Time Voltage T a C Version iux bytes bytes Sectors ns V AMD AM29LV001 128K _ varies 10 byte 45 4 5 5 5 2 4 7 205 AMD 201 001 128K varies 5 byte 45 4 5 5 5 2 4 7 20 Atmel AT49F002 256K varies byte 55 4 5 5 5 1 2 3 4 7 206 Atmel AT49F002T 256K varies 5 byte 55 4 5 5 5 1 2 3 4 7 206 Fujitsu MBM29F002T 256K varies 7 byte 55 4 5 5 5 2 4 7 20 Fujitsu MBM29F002B 256K varies 7 byte 55 4 5 5 5 2 4 7 205 Hyundai HY29F002T 256K varies 7 byt
12. Cloning seeeneennenznzznnnnnnzanznnzznzrnnznnzznninnnzenznnnzanzznzznzznnnza 46 8 22 Steps to Perform Cloning 46 52 2 LED 47 8 3 Cloning Questions een nU Re a 47 8 3 MAC AGdEt6ess c inet tent ipee 47 8 3 2 Different re eris D Ra UO IEEE inter aes ae 48 8 3 3 Design Restrictions Di Dd RE ade ERR 48 9 Low Power Design and Support dece eos reef pude 49 9 1 Software Support for Low Power Sleepy Modes 52 9 2 Baud Rates in Sleepy sse nne ennemi terrenis 52 10 Id mory acce dinner sa 23 10 1 Making a RAM Only Board nn 53 10 1 1 Hardware Changes s i ssssessssaceiscesseascasetiassavcascndsteascsescnsesicdassedanineadsadidandesiedansesnesceaatesagasdis 53 10 1 2 Software Chatiges 54 cesi meon 55 11 1 Supporting Other Flash Devices 58 11 2 Writing Your Own Flash Driver 59 iv rabbit com Table of Contents 12 Troubleshooting Tips for New Rabbit Based Systems 61 12 l Mriitial EE 61 12 2 Diagnostic Tests aite inti ED OU ERREUR E UR at 61 12 2 1 Program to Transmit Diagnostic Tests nennen 61 12 2 2 Diagnostic Test 1 Toggle the Statu
13. Programming Rabbit Cable Microprocessor Level Conversion x PC Serial Programming Port Connector Dynamic C programming uses the Rabbit s serial port A for software development However it is possible with some restrictions for the user s application to also use port A Rabbit 2000 Designer s Handbook rabbit com 1 rabbit com Introduction Semiconductor Chapter 2 Rabbit Hardware Design Overview Because of the glueless nature of the external interfaces especially the memory interface it is easy to design hardware in a Rabbit based system More details on hardware design are given in the Rabbit 2000 Microprocessor User s Manual 2 1 Design Conventions e Include a standard Rabbit programming cable The standard 10 pin programming connector provides a connection to serial port A and allows the PC to reset and cold boot the target system Connect a static RAM having at least 32K bytes to the processor using CS1 OE1 and WE1 It is use ful if the PC board footprint can also accommodate a RAM large enough to hold all the code antici pated If a large RAM can be accommodated software development will go faster Although code residing in some flash memory can be debugged debugging and program download is faster to RAM There are also types of flash memory that can be used but they cannot support debugging e Connect a flash memory that is on the approved list and has at
14. SLates id iie ont taie OR teases 33 watch expressions seen 33 Write en ble ote aerei ft 3 X 30 KTALAT 61 2 zero frequency current draw 50 76 rabbit com
15. This table can be found by search ing for the label FlashData in the file LIB BIOSLIB FLASHWR LIB The format is described in the file and consists of the flash ID code the sector size in bytes the total number of sectors and whether the flash is written one byte at a time or one entire sector at a time 2 Near the top of the main BIOS file BIOSNRABBITBIOS C for most users in the line define FLASH SIZE FLASH SIZE change FLASH SIZE toa fixed value for your flash the total size of the flash in 4096 byte pages 3 Ifa version of Dynamic C prior to 7 02 is being used the macro SECTOR SIZE near the top of LIB BIOSLIB FLASHWR LIB needs to be hard coded a manner similar to step 2 above In the line define MAX FLASH SECTORSIZE SECTOR SIZE SECTOR SIZE should be replaced with the sector size of your flash in bytes Note that prior to Dynamic C 7 20 the BIOS only supported flash devices with equally sized sectors of either 128 256 512 1024 or 4096 bytes 1 small sector flash If you are using an older version of Dynamic C prior to version 7 20 and your flash device does not fall into that category it may be possible to support it by rewriting the BIOS flash functions see Section 11 2 for more information Starting with Dynamic C 7 20 large sector flash devices are supported by the BIOS Typically large sector flash devices have a variety of sector sizes on a single chip 58 rabbit com Flash Memories 11 2 Writi
16. deactivate the all region In other words if an all region is active and a debug region is acti vated any nodebug code will still be generated to the a11 region until a nodebug region is made active Rabbit 2000 Designer s Handbook rabbit com 35 With regard to follow expressions a debug region may not follow a nodebug region or vice versa An all region may follow either a debug or a nodebug region Only an a11 region may follow another all region This allows debug and nodebug regions to spill into a common a11 region 6 5 3 Origin Statement Examples Figure 6 2 shows how the origin statements define the mapping between the logical and physical address spaces define DATASEGVAL rvarorg rootdata grows down rcodorg rootcode wcodorg watcode xcodorg xmemcode DATASEGVAL Oxc5ff 0x6600 apply 0x0000 0x6000 apply DATASEGVAL 0xc600 0x0400 apply 0 000 0 1 000 apply data declarations start here Dynamic defines macros that include information about compiling to or flash and identifying memory device types memory sizes and board type The origin setup shown above differs from that included in the standard BIOS included with Dynamic C as the standard BIOS uses additional macros val ues for dealing with a wider range of boards and memory device types Logical Address Space OxFFFF OxE000 OxCDFF OxC5FF 0x6000 0x0000 Figure 6 2 Logical to physical mapping xmemcode st
17. fast cloning restrictions and options please see Technical Note 207 Rabbit 2000 Cloning Board This document may be found the Rabbit website www rabbit com rabbit com docs 8 2 Creating a Clone Before cloning can occur the master controller must be readied Once this is done any number of clones may be created from the same master 8 2 1 Steps to Enable and Set Up Cloning The step by step instructions to enable and set up cloning on the master are in Technical Note 207 In brief the steps break down to attaching the programming cable running Dynamic C making any desired changes to the cloning macros and then compiling the BIOS and user program to the master The only cloning macro that must be changed is ENABLE CLONING since the default condition is clon ing is disabled 8 2 2 Steps to Perform Cloning Once cloning is enabled and set up on the master controller detach the programming cable and attach the cloning board to the master and the clone Make sure the master end of the cloning board is connected to the master controller the cloning board is not reversible and that pin 1 lines up correctly on both ends Once this is done reset the master by hitting Reset on the cloning board The cloning process will begin 46 rabbit com BIOS Support for Program Cloning 8 2 3 LED Patterns The following table describes the LED patterns that may occur on the Cloning Board Table 8 1 LED Patterns on Cloning Board Clo
18. kHz The 48 bit battery backable clock continues to operate without interruption Usually the programmer will want to reduce power consumption to a minimum either for a fixed time period or until some external event takes place On entering sleepy mode by calling use 32kHzOsc the periodic interrupt is completely disabled the system clock is switched to 32 768 kHz and the main oscillator is powered down On exiting sleepy mode by calling use MainOsc the main oscillator is powered up a time delay is inserted to be sure that it has resumed regular oscillation and then the system clock is switched back to the main oscillator At this point the periodic interrupt is reenabled Data will probably be lost if interrupt driven communication is attempted while in sleepy mode While in sleepy mode the user has available a routine updateTimers that can be called periodi cally to keep Dynamic C time variables updated These time variables keep track of seconds and millisec onds and are normally used by Dynamic C routines to measure time intervals or to wait for a certain time or date This routine reads the real time clock and then computes new values for the Dynamic C time vari ables The normal method of updating these variables is the periodic interrupt that takes place 2048 times per second 9 2 Baud Rates in Sleepy Mode The available baud rates in sleepy mode are 1024 1024 2 1024 3 1024 4 etc The baud rate 113 77 is available as 10
19. let to exit the cold boot upon completion 80 14 05 MBOCR Map SRAM on CS1 OE1 WE1 to Bank 0 80 09 51 ready watchdog for disable 80 09 54 disable watchdog timer code to be loaded in SRAM goes here 80 24 80 Terminate boot strap start executing code at address Zero The program serialIO exe has the ability to automatically increment the address Instead of typing in all the addresses you can use some special comments They are case sensitive and must be at the begin ning of the line with no space between the semicolon and the first letter of the special comment Address nnnn Triplet The first special comment tells the program to start at address nnnn and increment the address for each transmitted data byte The second special comment disables the automatic address mode and directs the program to send exactly what is in the file The triplets shown in 3 may be rewritten as Address 0000 21 01 00 pid hl 1 06 10 1 b 16 7E ld a hl 29 add hl hl 10 FC djnz loop C3 00 00 jp 0 Triplet Rabbit 2000 Designer s Handbook rabbit com 65 66 rabbit com Troubleshooting Tips for New Rabbit Based Systems Semiconductor Appendix A Supported Rabbit 2000 Baud Rates This table contains divisors to put into TATXR registers All frequencies that allow 57600 baud up to 30MHz are shown as well as a few higher frequencies
20. oscillator frequency 12 2 Diagnostic Tests The cold boot mode may be used to communicate with the target system without using Dynamic C As dis cussed in Section 4 1 in cold boot mode triplets may be received by serial port A or the slave port To load and run the diagnostic programs the easiest method is to use the programming cable and a specialized ter minal emulator program over asynchronous serial port A To use the slave port requires more setup than the serial port method and it is not considered here Since each board design is unique it is not possible to give a one size fits all solution for diagnosing board problems However using the cold boot mode allows a high degree of flexibility Any sequence of triplets may be sent to the target 12 2 1 Program to Transmit Diagnostic Tests The SerialIO_1 zip is available for download at www rabbitsemiconductor com support downloads The zip file contains the specialized terminal emulator program seriallO exe and several diagnostic programs The diagnostic programs test a variety of functionality and allow the user to simulate some of the behavior of the Dynamic C download process Rabbit 2000 Designer s Handbook rabbit com 61 After extracting the files double click on 1 1 to display the following screen a Serial 1 0 20010420 Help Baud x e rar DSR 2400 None gt 2 3 4 RTS Break CTS Transmit
21. power pins should be connected by a low inductance path to the power plane or if there is no power plane to a decoupling capacitor For capacitors immediately adjacent to the processor use 10 nF decoupling capacitors 01 uF Larger capacitors have too much inductance resulting in excessive harmonics above 100 MHz Figure 3 6 Decoupling capacitor placement and layout Rabbit 2000 Vss gt Von Decoupling of pin 42 Vy is not critical since relatively small currents flow through this pin Rabbit 2000 Designer s Handbook rabbit com 17 3 4 2 5 Elimination of Power Plane If the power plane is eliminated or extensively slotted to accommodate routed traces decoupling and power distribution becomes more critical The key is to maintain a low inductance connection from hot package power pins to a decoupling capacitor Also keep the inductance between widely separated parts of the power net as low as possible Gridding the net in a cross connect pattern will lower inductance between points as will wider traces The procedure is to use a grid and then use wide traces from grid intersections to the decoupling capacitors or packages Figure 3 7 Power Distribution Grid O O Decoupling O Wide Trace gt Capacitor 18 rabbit com Core Design and Components Semiconductor Chapter 4 How Dynamic C Cold Boots th
22. resulting in more radiation from the external circuit due to its higher frequency In either case there should not be excessive radiation from this circuit if layout guidelines are followed The main objective is to keep the loop area of the circuit small so as to avoid coupling the clock to other lines and because current circulating in a loop acts as an antenna The part of the circuit most susceptible to radiation is the trace from pin 91 to the 2 kQ resistor see Figure below The remainder of the circuit has the edges slowed by the 2 kQ resistor The low frequency of the 32 768 kHz clock causes no radiation Figure 3 4 Loop area of the circuit should be kept small XTALB2 91 2kQ 33 a 1 1 MO Current Crystal typ 11 05 MHz Loop 20 pF I XTALB 90 33 pF l Rabbit 2000 Designer s Handbook rabbit com 15 Copper pour connected to ground plane Figure 3 5 Avoid coupling the clock to other lines Vss XTALBI XTALB2 Rabbit 2000 Table 3 1 High Speed Crystal Oscillator Component Component Description Value Name CLI Input Cap 33 pF CL2 Output Cap 33 pF Rp Bias Resistor 1 MQ Rs Current Limiting Series Resistor 2 KQ High speed oscillator CL 20 pF 16 rabbit com Core Design and Components 3 4 2 4 Processor D
23. to invert address lines A18 and A19 after the logical to physical address conversion This allows each 256K quadrant of physical memory access up to four 256K pages on the actual memory device These would be used for special compilations of programs to be coresident on flashes between 512k and 1M in size See Application Note 202 Rabbit Memory Management Ina Nutshell and Application Note 210 Running Two Application on a TCP IP Development Board for more details See the top of the BIOS source code BIOS RabbitBIOS for more options Rabbit 2000 Designer s Handbook rabbit com 33 6 5 Origin Statements to the Compiler The Dynamic C compiler uses the information provided by origin statements to decide where to place code and data in both logical and physical memory The origin statements are normally defined in the BIOS however they may also be useful in an application program for certain tasks such as compiling a pilot BIOS or cold loader or special situations where a user wants two application coresident within a single 256K quadrant of flash 6 5 1 Origin Statement Syntax Prior to Dynamic C 7 05 origin statement syntax is lt origin type gt lt origin name gt lt segment value gt lt logical address gt lt Size gt apply All arguments are required Starting with Dynamic C 7 05 origin statement syntax in BNF is origin directive ttorigin tvpe identifier origin designator origin designator action expressio
24. write protection The unlock operation involves a special sequence of reads and writes accessing special addresses and writing the unlock codes Another consideration is that the flash memory may be divided into sectors An entire sector must be writ ten to modify the memory Small sector memories are divided into 1024 sectors If the largest flash mem ory that is usable in a particular design is 512K the largest sector size is 512 bytes If the smallest memory used is 128K then the smallest sector is 128 bytes In order that the sector can be contiguous for all possi ble types of memory the lower 7 address lines A0 A6 should be permuted as a group Address lines A7 and 8 should not be permuted at all if it is desirable to keep the larger sectors contiguous The upper 10 address lines can be permuted as a separate group The special memory chip addresses 05555h and must be accessed as part of the unlock sequence These addresses use only the first 16 address lines and have the odd and even numbered bits the same The unlock codes use the numbers 55h AAh or AOb Permuting data or address lines with flash memory should probably be avoided in practical systems Rabbit 2000 Designer s Handbook rabbit com 11 3 4 Board Layout and Electromagnetic Interference Most design failures are related to the layout of the printed circuit board PCB A good layout results when the effects of electromagnetic interference a
25. 24 9 and may be useful for communicating with other systems operating at 110 bps a 3 4 mismatch In addition the standard PC compatible UART 16450 with a baud rate divider of 113 generates a baud rate of 1019 bps a 0 5 mismatch with 1024 bps Baud rate mismatches of up to 5 may be tolerated If there is a large baud rate mismatch the serial port can usually detect that a character has been sent to it but can not read the exact character 52 rabbit com Low Power Design and Support Semiconductor Chapter 10 Memory Planning The following requirements should be considered when planning memory configuration for a Rabbit sys tem The size of the code anticipated Usually code size up to 512K is handled by one flash memory chip Static data tables can be conveniently placed in the same space using the xdata and xst ring decla rations supported by Dynamic C so the amount of space needed for static data can be added to the amount of space needed for code If you are writing a program from scratch remember that 512K of code is equivalent to 25 000 to 50 000 C statements and such a large program can take years to write Dynamic programs vary in how much RAM will be required Many programs can subsist on 32K of RAM Having more RAM is convenient for debugging since debugging and program testing generally operate more powerfully and faster when sufficient RAM is available to hold the program and data For this reason most Rabbit
26. Bh 2 RAM access time nanoseconds 42 rabbit com The System ID Block Table 7 1 The System ID Block Continued ae di p Size bytes Description 2Dh 2 CPU ID 2Fh 4 Crystal frequency Hertz 33h 6 Media Access Control MAC address 39h 24 Serial number as a null terminated string 51h 30 Product name as a null terminated string 6Fh N Reserved variable size SIZE 10h 4 Size of this ID block SIZE 2 Size of user block SIZE 2 Offset of user block location from start of this block SIZE 08h 2 CRC value of this block when this field 0000h SIZE 06h 6 Marker should 55h AAh 55h 55h Rabbit 2000 Designer s Handbook rabbit com 43 44 rabbit com The System ID Block Semiconductor Chapter 8 BIOS Support for Program Cloning The BIOS supports copying designated portions of flash memory from one controller the master to another the clone The Rabbit 2000 Cloning Board connects to the programming port of the master and to the programming port of the clone Figure 8 1 Cloning Board gt a Connect Connect to Master to Clone Programming Programming Port Port 8 1 Overview of Cloning If the cloning board is connected to the master the signal CLKA is held low This is detected in the BIOS after the reset ends invoking the cloning support of the BIOS If cloning has been enabled in the master s BIOS it will c
27. C It also normally contains a software interface to the user s particular hardware Certain drivers in the Dynamic C libraries require BIOS routines to perform tasks that are hardware dependent The BIOS also e Provides a variety of low level services for the user s program Takes care of microprocessor system initialization e Provides the communications services required by Dynamic C for downloading code and performing debugging services such as setting breakpoints or examining data variables e Defines the setup of memory A single general purpose BIOS is supplied with Dynamic C for the Rabbit This BIOS will allow you to boot Dynamic C on any Rabbit based system that follows the basic design rules needed to support Dynamic C The BIOS requires both a flash memory and a 32K or larger RAM or just a 128K RAM for it to be possible to compile and run Dynamic C programs If the user uses a flash memory from the list of flash memories that are already supported by the BIOS the task will be simplified If the flash memory chip is not already supported the user will have to write a driver to perform the write operation on the flash memory This is not difficult provided that a system with 128K of RAM and the flash memory to be used is available for testing An existing BIOS can be used as a skeleton BIOS to create a new BIOS Frequently it will only be neces sary to change def ine statements at the beginning of the BIOS In this case it is u
28. IB should be called int readIDBlock int flash bitmap DESCRIPTION Attempts to read the system ID block from the highest flash quadrant and save it in the system ID block structure It performs a CRC check on the block to verify that the block is valid If an error occurs SysIDBlock tableVersion is set to zero PARAMETER flash bitmap Bitmap of memory quadrants mapped to flash Examples 0x01 quadrant 0 only 0x03 quadrants 0 and 1 0x0C quadrants 2 and 3 RETURN VALUE 0 Successful 1 Error reading from flash 2 ID block missing 3 ID block invalid failed CRC check 7 2 2 Writing the System ID Block The WriteFlash function does not allow writing to the ID block If the ID block needs to be rewrit ten a utility to do so 1s available for download from the Rabbit website http www rabbit com support feature downloads html or contact Rabbit Semiconductor s Technical Support Rabbit 2000 Designer s Handbook rabbit com 41 7 3 Determining the Existence of the System ID Block The following sequence of events can be used to determine if a system ID block is present 1 The top 16 bytes of the flash device are read 16 bytes starting at address 0 3 0 will be read if a 256KB flash is installed into a local buffer The top 6 bytes of the buffer read from 0x3FFF8 0x3FFFF are checked for an alternating sequence of 0x55 OxAA 0x55 OxAA 0x55 OxAA If this is not found the block does not exist a
29. RAM and functioning or the program will not execute correctly A series of triplets are sent to the Rabbit via one of the bootstrap ports to set up the necessary control regis ters and write several instructions to RAM Finally the bootstrap termination code is sent and the program begins executing instructions in RAM starting at address 0x00 The following steps illustrate one way to create a diagnostic program 1 Write a test program in assembly main boot ld 1 1 14 b 16 loop ld a hl add hl hl Shift left djnz loop 16 steps jp 0 continue test endasm 2 Compile the program using Dynamic C and open the Assembly window The disassembled code looks like this 7 Dynamic Dist 7 30P File Edit Run Inspect Options Window Help Edit Disassembled Code 1c46 0610 ld 1c48 7E ld 1c49 29 add 1 4 10 djnz 1 4 30000 ali 64 rabbit com Troubleshooting Tips for New Rabbit Based Svstems 3 The opcodes and their data are in the 2nd column of the Assembly window Since we want each triplet loaded to RAM beginning at address zero create the following sequence of triplets code to be loaded in SRAM 00 00 21 00 01 01 00 02 00 00 03 06 00 04 10 00 05 7 00 06 29 00 07 10 00 08 FC 00 09 C3 00 OA 00 00 OB 00 4 The code to be loaded in SRAM must be flanked by triplets to configure internal peripherals and a trip
30. Rabbit starts up after a reset and maxi mum wait states are enabled there will not be a problem Nor will there be a problem if wait states are inserted to conserve power Controller boards produced by Rabbit Semiconductor will not experience the wait state bug unless the default setup in the BIOS is overridden Rabbit Semiconductor flash write routines may move code into RAM memory and execute it there in order to perform a write on the flash code memory These routines automatically avoid any wait state bug prob lems Wait states in memory used for data are not a problem because of the compiler directive that can be used to avoid the bug There is no reason to avoid wait states for data memory 74 rabbit com Wait State Bug Semiconductor Index Sym bols diagnostic tests 61 65 21 3 9 53 e MC PTT 3 9 30 33 53 64 E RESET tiv D NP HU 61 iii e dliel i i adds 12 18 ATIS and A19 33 address line inversion 2 33 flash known types 58 B line permutation s seesensenenzanennenznzanznnezznnazzni 11 floating inputs 4 eene 49 baud rates Clock frequencies 22 3 default val e 4 2 eerte erento 32 Muro 21 identification information 3 program loading 2 21 J sleepy mode svi niii eene 52 BIO
31. S eee 21 22 29 37 39 JEDEC write sequence 2 58 GLK np e RR Ne 14 non approved memories 3 M Wait 100 eere nnne EE o temm 30 boot ROM 20 memory C ACCOSS 9 address line inversion 0 33 chip select metre etd 3 9 20 23 available 33 pin T 14 61 bank control registers sese 30 jd 7 basic system se 4 24 battery backable sse 3 battery backed sse 23 distribution eee 50 cycle at 32 kHz aedes eet 50 frequencies amp baud rates 3 flash and line permutation 11 speed cce ente peer ie eter ie 32 known flash types 58 Cloning spona a 32 logical segments 2 24 cloning and 3 physical space sse 23 cold BOGE 3 20 62 root variables 2 53 cold loader eee 21 34 37 54 Sector 51265 23 Conformal coating 8 sector write time 20 2 24 3 SRAM A 3 33 stack Pages 53 current consumption 8 supported 55 writing a flash driver 22 2 0 59 60 D rec ee 30 data segment 33 MMU and
32. Semiconductor controllers based on the Rabbit use a dual footprint for RAM that can accommodate either a 32K x 8 which is in a 28 pin package or a 128K x 8 or 512K x 8 which is in a 32 pin package The base RAM is interfaced to CS1 WE1 and OEI RAM is required for the following items Root variables maximum of 48K Stack pages rarelv more than 20K RAM for debugging convenience on prototype units 512K is usually enough to accommodate programs RAM for extended memory such as data logging applications or communications applications The amount needed depends on application 10 1 Making a RAM Only Board Some Rabbit customers are designing boards that have only a single RAM chip and no flash memory Although this is not generally recommended it may be safe to use only a RAM chip as long as the board has a continuous power supply and is set up to be field programmable via the Rabbit bootstrap mode For example a Rabbit board in a noncritical system such as a lawn sprinkler system may be monitored from a remote location via the Internet or Ethernet where the remote monitor has the ability to reload the application program to the board One way to achieve field programmability is with the RabbitLink Net work Gateway There are certain hardware and software changes that are required to make this work which are discussed here Dynamic C starting with version 6 57 has the software files discussed here which are necessary to make a RAM o
33. a particular flash device uses to write data Currently only two common modes are defined sector writing mode as used by the SST SST29 and Atmel AT29 series writeMode 1 and byte writing mode as used by the Mosel Vitelic V29 series write Mode 2 other values of wr iteMode are currently undefined although they may be defined by Rabbit Semiconductor as new flash devices are used _InitFlashDriver This function is called from the BIOS A bitmap of quadrants mapped to flash 0x01 0x02 0x04 0x08 correspond to the Ist 4th quadrants 0 0 the topmost two quadrants is passed to it in HL This function needs to perform the following actions 1 Load FlashInfo flashXPC with the proper XPC value to access flash memory address 00000h via XMEM address E000h The quadrant number for the start of flash memory is passed to the function in HL and can be used to determine the XPC value if desired For example if your flash is located in the third memory quadrant the physical address of the first flash memory location is 80000h 80000h 000 72000h so the value placed into FlashInfo XPC should be 721 2 Load FlashInfo sectorSize with the flash sector size in bytes 3 Load FlashInfo numSectors with the number of sectors on the flash 4 Flashinfo writePtr should be loaded with the memory location in RAM of the function that will perform that action The function will need to be copied from flash to RAM at this time as
34. abbit com Core Design and Components 3 4 2 Layout and Decoupling for Low EMI Generally you should design with a 4 or more layer printed circuit board The cost of a 4 layer board as compared to a 2 layer board is about 30 more per square inch and generally well worth it Although we have not attempted it a 2 layer design would probably work for lower clock frequencies if the ground and power nets are well gridded for power distribution see Section 3 4 2 5 on page 18 Usually a 4 layer printed circuit board has a ground plane and a power plane located as the two inner lay ers and connect layers on the top and bottom layers Components may be mounted on only one side or on both sides A 6 layer board places the ground and power layers as the middle two layers and then has two routing layers both above and below Adjacent routing layers run traces at right angles to minimize cou pling between signal traces Sometimes the ground and power layers are placed on the outside of the boards but this makes debugging more difficult and compromises the layers more since they have to be cut up for the component footprints 3 4 2 1 EMI Sources Most EMI comes from signals that are strictly regular The main sources are the crystal oscillator the lines emanating from the Rabbit chip that are affected by the internal clocking of the chip and the actual clock or clock 2 if it is run around the printed circuit board Address and data lines generate less EMI be
35. ack watcode rootdata rootcode Physical Address Space OxFFFFF Ox9DDFF rootdata watcode 0x97000 0x20000 xmemcode 0x06000 rootcode 0x00000 36 rabbit com The Rabbit BIOS 6 5 4 Origin Directives Program Code To place programs in different places in root memory or to compile a boot strapping program such as a pilot BIOS or cold loader origin statements may be used in the user s program code For example the first line of a pilot BIOS program pilot c would be rcodorg rootcode 0 0 0 0 0x6000 apply A program with such an origin directive could only be compiled to a bin file because compiling it to the target would overwrite the running BIOS Rabbit 2000 Designer s Handbook rabbit com 37 38 rabbit com The Rabbit BIOS Semiconductor Chapter 7 The System ID Block The BIOS supports a system identification SysID block to be placed at the top of flash memory Identifi cation information for each device can be placed in it for access by the BIOS flash driver and users This block will contain specific part numbers for the flash and RAM devices installed the product s serial num ber Media Access Control MAC address if an Ethernet device and so on In addition the ID block is designed with future expansion in mind by including a table version number and storing the block s size in bytes within the block itself Pointers for a user
36. adiation at higher harmonics of the frequency Place the resistor which might be around 1 ohms as close to pin 1 as possible The capaci tive load of whatever the clock line is connected to along with the resistor creates an RC time constant that slows the edge If the capacitive load is larger a smaller resistor is needed and vice versa The clock line should be kept as short as possible and run over a ground plane or even better between two ground planes It should be positioned well away from other traces especially traces running parallel to it for any distance Coupling to a parallel trace is greater the faster the edges If you run parallel ground traces or a ground trace above the clock line then the parallel ground traces should be connected with very low inductance connections to the ground plane This is done by using many feedthroughs Figure 3 3 Many feedthroughs provide very low inductance connections between parallel ground traces and a ground plane Feedthroughs to 1 Ground Plane o e e Parallel Ground Traces 14 rabbit com Core Design and Components 3 4 2 3 High Frequency Oscillator Circuit The Rabbit s oscillator circuit typically runs at 11 05 MHz for a 22 1 MHz internal clock The internal clock doubler is used to double the clock frequency If the clock doubler is not used then the external oscil lator circuit runs at the full internal clock frequency
37. advantage of the faster access time offered by RAM The root memory segment holds a mixture of code and constants C functions or assembly language pro grams that are compiled to the root memory segment are interspersed with data constants Data constants are inserted between blocks of code Data constants defined inside a C function are put before the end of the code belonging to the function Data constants defined outside of C functions are stored as encountered in the source code Except in small programs the bulk of the code is executed using the xmem segment But code in the root memory segment operates slightly faster also the root memory segment has special properties that make it better for some types of code 5 2 2 1 Types of Code Best Suited for the Root Memory Segment e Short subroutines of about 20 instructions or less that are called frequently will use significantly less execution time if placed in root memory because of the faster calling linkage for 16 bit versus 20 bit addresses For a call and return 20 clocks are used compared to 32 clocks Interrupt routines Interrupts use 16 bit addressing so the entry to an interrupt routine must be in root e The BIOS core The initialization code of the BIOS must be at the start of the root memory segment Rabbit 2000 Designer s Handbook rabbit com 25 5 2 3 The Data Segment The data segment is mapped to RAM and contains C variables Typically it starts at 8K or above and en
38. all lddr func This change causes the block move to proceed at 11 clock cycles per byte on average rather than 7 clock cycles per byte Rabbit 2000 Designer s Handbook rabbit com 69 For small memory blocks lt 45 bytes it is more efficient to write the following code start ldi ldi jp nov start 141 start ldr ldr jp nov start ldr B 3 Wait States in Code Memorv There are two manifestations of the wait state bug in code memory If wait states are enabled there are cer tain instructions that will execute incorrectly and there are certain other instructions whose use will reduce the length of the output enable signal B 3 1 Instructions Affected by the Wait State Bug If wait states in code memory are enabled the 20 instructions in the table below execute incorrectly and should not be used Table B 1 Rabbit 2000 Instructions set b ix d set b iy d res b ix d res b iy d bit b ix d bit b iyd rl ix d rl iy d ix d ty d rr ix d rr iyd ix d iy d sla ix d sla iv d sra ix d sra iy d srl ix d srl iy d These instructions work correctly if there are zero wait states If wait states are desired equivalent instruc tions work without any problem For example SRA 8 13 clocks can be replaced by LD 1 8 9 clocks SRA B 4 clocks LD IX48 B 10 clocks 70 rabbit com Wait Stat
39. application program image file in the case of the RFU by compiling the BIOS straight to the target in the case of Dynamic C One of the first things the BIOS does in program mode is copy itself to flash and then transfer execution to the flash copy When the board pow ers up later without the programming cable attached it will start running the BIOS in flash The special BIOS BTOS RAMONLYBIOS eliminates the self copy step and initializes the MIU MMU correctly to match the hardware configuration This BIOS can be selected as the user defined BIOS by using the Options Compiler dialog box 54 rabbit com Memory Planning Semiconductor Chapter 11 Flash Memories The flash memories listed in the table below have been qualified for use with the Rabbit 2000 micropro cessor Starting with Dynamic C version 7 20 large sector flash devices sectors greater than 4096 bytes are supported To incorporate a large sectored flash into an end product the best strategy is have a small sectored development board IMPORTANT The rapidly changing market for flash devices may affect availability The inclusion of a flash device in the following table does not speak to its availability Table 11 1 32 Pin Flash Memories Supported by the Rabbit 2000 Small Sector Device Sector Number l Best Operating Vendor Name Sze Size
40. block of protected data exist as well with the planned use for storage of calibration constants etc although the user may use it if desired Note that version 1 of the ID block tableVersion 0x01 has only limited functionality In particular only the following parameters are valid tableVersion product ID timestamp macAddr idBlockSize idBlockCRC and marker Version 2 and later ID blocks have all the values filled with the exception of the flash and RAM speed fields and Dynamic C versions 7 04x2 and later support use of the user block If Dynamic C does not find a system ID block on a device the compiler will assume that it is a BL1810 Jackrabbit board Rabbit 2000 Designer s Handbook rabbit com 39 7 1 Definition of SysIDBlock The following global struct is defined in IDBLOCK LIB and is loaded from the flash device during BIOS startup Users can access this struct in RAM if they need information from it The definition below is for a 128 byte ID block the actual size can vary according to the value in idBlockSize The reserved field will expand and or shrink to compensate for the change in size typedef struct int tableVersion version number for this table layout int productID Rabbit part int vendorID 1 Rabbit char timestamp 7 YY M D H M S long flashID Rabbit part int flashType Write method int flashSize in 0x1000 pages int sectorSize size of flash secto
41. bout the same as reducing the clock speed by 30 Going from 0 to 2 wait states is worth approximately a 45 reduction in clock speed A table of memory access times required for various clock speeds is given in the Rabbit 2000 Microprocessor User 5 Manual 3 2 2 Precautions for Unprogrammed Flash Memory If a Rabbit based system is powered up and released from reset when not in one of the cold boot modes the processor attempts to begin execution by reading from address zero of the memory attached to CSO OEO and WEO If this memory is an unprogrammed or improperly programmed flash memory there is a danger that the memory could be destroyed if the write security feature of the flash memory is disabled Flash memories have a write security feature that inhibits starting write cycles unless a special code is first stored to the memory For example Atmel flash memories use the bytes AAh 55h and AOh stored to addresses AAAAh or 5555h in a particular sequence Any write executed that is not prefixed by this sequence will be ignored If the memory has write protection disabled and execution starts it is possible that an endless loop that includes a write to memory will establish itself Since the flash memory wears out after a few hundred thousand writes the memory could be damaged in a short period of time by such a loop Unfortunately flash memory is shipped from the factory with the protection feature disabled to accommodate obsolete memory programm
42. cause there is no regular frequency on these lines since the bus cycles vary in length shifting the signal phase constantly AO is the hottest address line since it is varying most rapidly and also has a stronger drive than the other address lines A square wave has harmonics at odd frequencies that decline in amplitude proportional to 1 f A small wire that acts as an antenna radiates more the higher the frequency of excitation The effectiveness as an antenna increases proportional to frequency These two effects approximately cancel resulting in an approximately flat spectrum for a typical printed circuit board For example without taking precautions it would not be unusual to have a problem with the 7th harmonic or 154 7 MHz when the Rabbit clock is 22 1 MHz Above approximately 300 MHz the edges are not fast enough to generate strong harmonics for typical Rabbit systems Rabbit 2000 Designer s Handbook rabbit com 13 3 4 2 2 Clock Signal Pin 1 Pin 1 of the Rabbit can be programmed to output the internal clock or the internal clock divided by 2 The Rabbit BIOS automatically disables this pin starting with Dynamic C 7 01 To minimize EMI avoid using this pin as a clock output Most Rabbit designs do not need to explicitly use the clock output pin However in cases that require a clock use clock 2 if possible Also a series resistor can and should be placed in the clock line to slow down the rise and fall times which will reduce r
43. ce 5 3 How The Compiler Compiles to Memory The compiler generates code for root code root constants extended code and extended constants It allo cates space for data variables but except for constants does not generate data to be stored in memory Any initialization of variables must be accomplished by code since the compiler is not present when the program starts in the field 5 3 1 Placement of Code in Memory Code may be placed in either extended memory or root memory Functions execute at the same speed but calls to functions in root memory are slightly more efficient than calls to functions in extended memory In all but the smallest programs most of the code is compiled to extended memory Since root constants share the memory space needed for root code as the memory needed for root constants increases the amount of code that can be stored in root memory decreases and code must be moved to extended mem ory 26 rabbit com Rabbit Memory Organization 5 3 2 Paged Access Extended Memory The code in extended memory executes in the 8K window from 0xE000 to OxFFFF This 8K window uses paged access Instructions that use 16 bit addressing can jump within the page and also outside of the page to the remainder of the 64K logical space Special instructions particularly 1 11 1 lret used to access code outside of the 8 window When one of these transfer of control instructions is exe cuted both the a
44. cessarily a legal requirement to perform the tests It depends on the type of equipment and its intended use For example FCC regulations in the USA exempt industrial equip ment 3 4 1 2 Classes For EMI Testing FCC computer regulations divide equipment into two classes CLASS CLASS B Computer equipment meant for office use business Computer equipment meant for home use where a machines office computers television is likely to be nearby Less restrictive emissions requirement less than 50 dB uV M at 3 meters 50 dB relative to 1 microvolt per meter or 300 microvolts meter More restrictive emissions requirement 40 dBuV M or 100 uV M Note that for field strength 20 dB is a factor of 10 and 6 dB is a factor of 2 Field strength declines inversely with distance so at 10 meters the field strength for the same device will be about 3 10ths as large as at 3 meters which is approximately 10 dB less 20 dB is a factor of 10 10 dB is a factor of the square root of 10 or 1 3 16 3 16 10 These limits apply in the range of 30 230 MHz for the more restrictive CE test Above 230 MHz the limit is 7 dB higher Although the test range goes to 1 GHz with Rabbit based systems there will rarely be any concern above 300 MHz With a Rabbit based system it is easy to meet the Class B limits if proper PCB layout precautions are observed At Rabbit Semiconductor our target is to beat the Class B limit by 10 dB 12 r
45. ct for battery backed RAM A bit may be set in the MMIDR register to force CS1 to stay enabled low This capability can be used to counter a problem encountered when the chip select line is passed through a device that is used to place the chip in standby by raising CS1 when the power is switched over to battery backup The battery switchover device typically has a propagation delay that may be 20 ns or more This is enough to require the insertion of wait states for RAM access in some cases By forcing CS1 low the propagation delay is not a factor because the RAM will be always selected and will be controlled by OE1 and WEI If this is done the RAM will consume more power while not battery backed than it would if it were run with dynamic chip select and a wait state If this special feature is used to speed up access time for battery backed RAM then no other memory chips should be connected to and WEI 3 2 1 Memory Access Time The memory access time required depends on the clock speed and the capacitive loading of the address and data lines Wait states can be specified by programming to accommodate slow memories for a given clock speed Wait states should be avoided with memory that holds programs because there is a significant slowing of the execution speed Wait states are far more important in the instruction memory than in the data memory since the great majority of accesses are instruction fetches Going from 0 to 1 wait states is a
46. ddress and the view through the 8K window change allowing transfer to any instruction in the 1M physical memory space The 8 bit XPC register controls which of two consecutive 4K pages aligns with the 8K window there are 256 pages The 16 bit PC controls the address of the instruction usually in the region OxE000 to OxFFFF The advantage of paged access is that most instructions continue to use 16 bit addressing Only when a page change is needed does a 20 bit transfer of control need to be made As the compiler compiles code in the extended code window it checks at opportune times to see if the code has passed the midpoint of the window or OxF000 When the code passes OxF000 the compiler slides the window down by so that the code at OxXF000 x becomes resident at 0xE000 x This automatic pag ing results in the code being divided into segments that are typically 4K long but which can be very short or as long as 8K Transfer of control within each segment can be accomplished by 16 bit addressing Between segments 20 bit addressing is required Rabbit 2000 Designer s Handbook rabbit com 27 28 rabbit com Rabbit Memory Organization Semiconductor Chapter 6 The Rabbit BIOS When Dynamic C compiles a user s program to a target board the BIOS Basic Input Output System is compiled first as an integral part of the user s program The BIOS is a separate program file that contains the code needed to interface with Dynamic
47. des memory the microprocessor oscillator crystals the Rabbit standard programming port and in some cases a power controller and power supply Although modern designs usually use at least four layer printed circuit boards two sided boards are a viable option with the Rabbit especially if the clock speed is not high and the design is intended to operate at 2 5 V or 3 3 V factors which reduce edge speed and electromagnetic radiation Schematics illustrating the use of the Rabbit microprocessor are available at www rabbitsemiconduc tor com 3 1 Clocks The Rabbit has two built in oscillators The 32 768 kHz clock oscillator is needed for the battery backable clock aka the real time clock the watchdog timer and the cold boot function The high frequency main oscillator is generally used to provide the main CPU clock Figure 3 1 Rabbit 2000 Oscillator Circuits XTALA2 330 15 pF XTALB2 2 kQ 33 pF O VWV lt 10 MQ 2 12 5 32 768 kHz 1 20 11 0592 MHz I 1 XTALA1 15 pF XTALB1 33 pF a 32 768 kHz Oscillator b Main Oscillator The 32 768 kHz oscillator is slow to start oscillating after power on For this reason a wait loop in the BIOS waits until this oscillator is oscillating regularly before continuing the startup procedure The startup delay may be as much as 5 seconds Crystals with low series resistance R lt 35 kW will start faster If the clock is batter
48. dress 0x4002 for later use by the BIOS and the program ming port is set up to be a 19200 or 57600 baud serial port 6 The program enters a loop where it receives a fixed number of bytes which compose a secondary loader program pilot sent by the PC and writes those bytes to memory location 0x4100 After all of the bytes are received program execution jumps to 0x4100 7 The secondary loader does a wrap around test to determine how much RAM 1 available and reads the flash ID This information is made available for transmittal to Dynamic C when requested oo The secondary loader now enters a finite state machine FSM that is used to implement the Dynamic C Target Communications protocol Dynamic C compiles the core of the regular BIOS and sends it to the target at address 0x00000 which is still mapped to RAM Note that this requires that the BIOS core be 0x4000 or less in size Rabbit 2000 Designer s Handbook rabbit com 21 9 The FSM checks the memory location 0x4001 previously set to zero after receiving each byte When the compilation and loading to RAM of the BIOS is complete Dynamic C signals the target that it is time to run the BIOS by sending a one to 0x4001 10 The BIOS runs some initialization code including setting up the serial port for 115200 baud setting up serial interrupts and starting a new FSM 11 The BIOS code modifies a jump instruction at the beginning of the program so that the next time it ru
49. ds at 52K OxCFFF Data allocation starts at or near the top and proceeds in a downward direction It is also possible to place executable code in the data segment if it is copied from flash to the data segment This can be desirable for code that is self modifying code to implement debugging aids or code that controls write to the flash memory and cannot execute from flash In some cases RAM may require fewer wait states so code executes faster if copied to RAM 5 2 4 The Stack Segment The stack segment normally is from 52K to 56K 0xD000 0xDFFF It is always mapped to RAM and holds the system stack Multiple stacks may be implemented by defining several stacks in the 4k space or by remapping the 4K space to different locations in physical RAM memory or by using both approaches For example if 16 stacks of 1k length are needed then 4 stacks can be placed in each 4K mapping and 4 different mappings for the window can be used 5 2 5 The Extended Memory Segment This 8K segment from 56K to 64K 0xE000 0xFFFF is used to execute extended code and it is also used by routines that manipulate data located in extended memory While executing code the mapping is shifted by 4K each time the code passes the 60K point Up to a megabyte of code can be efficiently executed by moving the mapping of the 8K window using special instructions long call long jump and long return that are designed for this purpose This uses up only 8K of the 16 bit addressing spa
50. e 45 4 5 5 5 11 2 4 7 20 Hyundai HY29F002B 256K _ varies 7 byte 45 43535 15254 7 200 Package Types 1 32 pin PDIP 3 32 pin TSOP 8 mm 14 mm 5 44 pin PLCC 2 32 pin PLCC 4 32 pin TSOP 8 mm x 20 mm 6 48 pin TSOP 8 mm x 14 mm b These flash devices are supported as of the Dynamic C version listed but have not all been tested with those ver sions 512KB flash in particular may not work with versions prior to 7 04 but a software patch is available from Rabbit tech support for 512KB flash support under versions 6 57 and 7 03 c Dynamic C Versions 6 04 6 1x The FLASH SIZE parameter in the JRABBIOS C file needs to be changed to reflect the correct number of pages for the selected device By default the FLASH SIZE parameter contains a 0x20 that corresponds to 128K x 8 device with thirty two 4K pages of flash Dynamic C versions 6 5x and greater determine the flash size automatically and no code change is required Rabbit 2000 Designer s Handbook rabbit com 57 11 1 Supporting Other Flash Devices If a user wishes to use a flash memory not listed in the above tables but still uses the same standard JEDEC write sequences as one of the supported flash devices the existing Dynamic C flash libraries may be able to support it simply by modifying a few values in the BIOS Specifically three modifications need to be made 1 The flash device needs to be added to the list of known flash types
51. e Bug Any of the registers A H L can be used to hold the intermediate value so you should be able to find a free register For BIT 3 IX 4 10 clocks use LD B 4 9 clocks BIT 3 B 4 clocks If the atomic nature of the operation is important then the operation can be shifted to the hl index register For example SET 3 1 4 Use instead PUSH HL PUSH DE LD HL IX LD DE 4 ADD HL DE SET 3 HL POP DE POP HL B 3 1 1 Dynamic C version 7 05 Starting with version 7 05 Dynamic C does not generate any of the instructions in Table B 1 and they are not used in the library routines If any of these instructions are used in an application program a warning will be generated by the compiler B 3 1 2 Prior versions of Dynamic C In versions of Dynamic C prior to 7 05 the library SLICE LIB contains one of these instructions bit b iy d Do not use wait states with slice statements in these earlier versions of Dynamic C If any of the instructions in the table above are used in an application program no warning is generated and you are on your own Rabbit 2000 Designer s Handbook rabbit com 71 B 3 2 Output Enable Signal and Conditional Jumps If wait states are enabled for code memory the memory output enable signal is shortened by one clock cycle for the first byte read after any conditional jump instruction that does not jump This is not the same as losing a wait state and in some cas
52. e Target System Dynamic C assumes that target controller boards using the Rabbit CPU have no pre installed firmware Dynamic C takes advantage of the Rabbit s bootstrap cold boot mode that allows memory and I O writes to take place over the programming port Figure 4 1 Rabbit Programming Port Circuit Board with Rabbit 2000 Processor Programming RABBIT 2000 Header Programming Header Pinout The Rabbit programming cable is a smart cable with an active circuit board in its middle The circuit board converts RS 232 voltage levels used by the PC serial port to CMOS voltage levels used by the Rabbit When the programming cable connects a PC serial port to the target controller board the PC running Dynamic C is connected to the Rabbit as shown in Table 4 1 Table 4 1 Programming Port Connections PC Serial Port Signal Rabbit Signal DTR output RESET input reset system DSR input STATUS gen purpose output TX serial output RXA serial input chan A RX serial input TXA serial output chan A Rabbit 2000 Designer s Handbook rabbit com 19 The programming cable includes an RS 232 to CMOS signal level converter circuit The level converter is powered from the 5 V or 3 3 V power supply voltage present on the Rabbit programming connector see Figure 4 1 Plugging the programming cable into the Rabbit programming connector results in pulling the Rabbit SMODEO SMODE startup mode lines hi
53. ecoupling The internal clock of the processor is routed throughout the silicon die On the rising edge of the clock all the flip flops on the die are clocked within a nanosecond or so of each other resulting in large current flows through the ground and power pins The current surge is mainly due to the capacitance driven by the clock and by flip flops changing their state on the clock The connections from the ground and power pins to the die have inductance as do the connections within the die The ground and power on the die will bounce up and down at the clock frequency and this will be coupled to all the other I O lines that are clamped to power or ground by transistors To minimize this bouncing a low impedance path from the pairs of ground and power pins to decoupling capacitors should be provided The Rabbit has 6 power and 6 ground pins Of the six power pins five reside on the main power grid and are used to power the CPU peripherals and the I O The other one pin 42 resides on a separate power net to supply the battery backed clock The ground pins are all tied to the common ground network To minimize EMI connect all power pins as directly as possible to a ground plane running under the pro cessor without large slots or non metal areas in the plane A low inductance connection is obtained by a short and wide trace leading to the feedthrough to the ground plane A pair of feedthroughs has less induc tance than a single feedthrough The
54. ed for a variety of other purposes including user applications A device attached to the programming connector has complete control over the system because it can per form a hardware reset and load new software If this degree of control is not desired for a particular situa tion then certain pins can be left unconnected in the connecting cable limiting the functionality of the Rabbit 2000 Designer s Handbook rabbit com 3 connector to serial communications Rabbit Semiconductor will be developing products and software that assume the presence of the programming connector 2 1 2 Memory Chips Most systems have one static RAM chip and one or two flash memory chips but more memory chips can be used when appropriate Static RAM chips are available in 32K x 8 64K x 8 128K x 8 256K x 8 and 512K x 8 sizes The 256K x 8 is mainly available in 3 V versions The other chips are available in 5 V or 3 V versions Suggested flash memory chips between 128K x 8 and 512K x 8 are given in Chapter 11 Flash Memories Dynamic C and a PC are not necessary for the production programming of flash memory since the flash memory can be copied from one controller to another by cloning This is done by connecting the system to be programmed to the same type of system that is already programmed This connection is made with a cloning cable The cloning cable connects to both programming ports and has a button to start the transfer of program and an LED to dis
55. ensuring that the code is com pact and executes quickly NOTE The relative size of the root memory and data segments can be adjusted in 4K steps 24 rabbit com Rabbit Memory Organization 5 2 1 Definitions Extended Code Instructions addressed in the extended memory segment Extended Constants C constants addressed in the extended memory segment They are mixed together with the extended code Extended Memory Logical addresses above OxDFFF also known as xmem Extended RAM RAM not used for root variables or stack Extended memory in RAM may be used for large buffers to save root RAM space The function xalloc allocates space in extended RAM mem ory Root Code Instructions addressed in the root memory segment Root Constants C constants such as quoted strings or data tables addressed in the root memory segment Root Memory Logical addresses below 0xE000 Root Variables C variables including structures and arrays that are not initialized to a fixed value are addressed in the data segment 5 2 2 The Root Memory Segment The root memory segment has a typical size of 24K The larger the root memory segment the smaller the data segment and vice versa Root memory segment address zero is always mapped to 20 bit address zero Usually the root memory segment is mapped to flash memory since root code and root constants do not change except when the system is reprogrammed It may be mapped to RAM for debugging or to take
56. ent It explains how to develop a Rabbit microprocessor based system that can be programmed with Dynamic C With the a Rabbit microprocessor and Dynamic C many traditional tools and concepts are obsolete Com plicated and fragile in circuit emulators are unnecessary EPROM burners are not needed The Rabbit microprocessor and Dynamic C work together without elaborate hardware aids provided that the designer observes certain design conventions 1 1 Summary of Design Conventions e Include a programming connector Connect a static RAM having at least 32K bytes to the Rabbit 2000 using CS1 OE1 and e Connect a flash memory that is on the approved list and has at least 128K bytes of storage to the Rabbit 2000 using 80 0 and WEO e Install a crystal or oscillator with a frequency of 32 768 kHz to drive the battery backable clock Bat tery backing is optional but the clock is used in the cold boot sequence to generate a known baud rate Install a crystal or oscillator for the main processor clock that is a multiple of 614 4 kHz or better a multiple of 1 8432 MHz As shown in Figure 1 1 the Rabbit programming cable connects a PC serial port to the programming con nector of the target system Dynamic C runs as an application on the PC and can cold boot the Rabbit based target system with no pre existing program installed in the target Figure 1 1 The Rabbit Microprocessor and Dynamic C PC Hosts Dynamic
57. ent Flash Sizes Since the BIOS supports a variety of flash types the flash EPROM on the two controllers do not have to be identical Cloning works between master and clone controllers that have different sized flash chips because the master copies its own universal flash driver to the clone The flash driver determines the particulars of the flash chip that it is driving The master controller s BIOS must allocate a memory buffer sufficiently large to work on the target Prior to Dynamic C version 7 02 the cloning software used root memory for this buffer which reduces the root memory available to the application program The size of the buffer is given by the macro MAX FLASH SECTORSIZE This macro is defined near the top of the LIB BIO SLIB FLASHWR LIB file The default value is 1024 4096 in older versions The user can reduce this buffer size to the maximum of the master and target s sector sizes if root data space is a problem or increase it to 4096 if needed Starting with Dynamic C version 7 02 the cloning implementation uses xmem for the buffer so root data space will not be a problem and no changes should be made to FLASHWR LIB 8 3 3 Design Restrictions Digital I O line PB1 should not be used in the design if cloning is to be be used 48 rabbit com BIOS Support for Program Cloning Semiconductor Chapter 9 Low Power Design and Support To get the most computation for a given power level the operating voltage
58. er pilot BIOS at 19200 or 57000 baud depending on the version of Dynamic C 3 Run the secondary loader and load the BIOS as Dynamic C compiles it 4 Run the BIOS and load the user program at 115200 baud after Dynamic C compiles it to a file 4 2 1 Program Loading Process Details When Dynamic C starts the following sequence of events takes place 1 The serial port is opened with the DTR line high closed then reopened with the DTR line low at 2400 baud This pulses the reset line on the target low the programming cable inverts the DTR line and pre pares the PC to send triplets 2 A group of triplets defined in the file COLDLOAD BIN consisting of 2 address bytes and a data byte are sent to the target The first few bytes sent are sent to I O addresses to set up the memory mapping unit MMU and the memory interface unit MIU and do system initialization The MMU is set up so that RAM is mapped to 0x00000 and flash is mapped to 0x80000 3 The remaining triplets place a small initial loader program at memory location 0x00000 The last triplet sent is 0x80 0x24 0x80 which tells the CPU to ignore the SMODE pins and start running code at address 0x00000 4 The PC now bumps the baud rate on the serial port being used to 19200 or 57000 baud depending on the version of Dynamic C 5 The primary loader measures the crystal speed to determine what divisor is needed to set a baud rate of 19200 or 57600 The divisor is stored at ad
59. ers The solution to this problem is to order the memory with the write protection enabled or to enable it with a flash programming system Then the memory will be safe if it is soldered into the Rabbit system If an unsafe memory is soldered into a system then the memory can be powered up with the programming cable connected and a sequence can be sent using the cold boot procedure to enable the write protection Com piling any Dynamic C program to the flash will make the memory safe If this is not convenient tester Rabbit 2000 Designer s Handbook rabbit com 9 software can make the memory safe by sending a byte sequence over the programming connection serial link The following example shows a program that can be downloaded via the cold boot protocol to make a Atmel AT29C010A 128K x 8 flash memory safe In this case the RAM connected to CSI is used to hold a program starting at address zero The flash memory is mapped into the data segment starting at address 1000h for access to the start of the flash memory Before storing this program the RAM is mapped to the first quadrant The program resides at address zero in RAM NOTE this program has not been tested ld a 0eih ioi ld ld a 3fh ioi 1d 12h a 14 0 ld 15h a ld a 0aah ld ld a 55h ld ld a 0a0h ld ld 1 1000 ld 1 0 3 inc hl 1 1 00 1 ld 1 00 jz 5555h 1000h a 2AAAh 1000h a 5555h 1000h a 13
60. es that Dynamic C will communicate at 115 200 baud with the target If this macro 1 set to zero Dynamic will communicate at 57 600 baud The lower baud rate might be needed on some PCs that can not handle 115 200 baud If USE115KBAUD is changed to zero the baud rate should be changed to 57 600 in the Dynamic C Options Communications dialog box Starting with Dynamic C 7 05 USE115KBAUD is not available to change the baud rate simply choose the baud rate in Options Communications CLOCK DOUBLED The default value of 1 causes the clock speed to be doubled if the crystal speed is less than or equal to 12 9 MHz Setting this to zero means the clock speed will not be doubled ENABLE CLONING The default value of 0 disables cloning Setting this to 1 enables cloning and slightly increases the code size of the BIOS If cloning is used PB1 should be pulled up with 50K or so pull up resistor Various cloning options are available when ENABLE CLONING is set to one For more informa tion on cloning please see Chapter 8 BIOS Support for Program Cloning in this manual and or Technical Note 207 Rabbit 2000 Cloning Board which is available at rabbitsemiconduc tor com 32 rabbit com The Rabbit BIOS DATAORG Beginning logical address for the data segment The default is 0x6000 This should only be changed to multiples of 0x 1000 Increasing it increases the root code space available and decreas es root data space decreasing it has the oppo
61. es the shortened output enable signal will not cause a problem The conditional jump instructions are jp cc mn cc condition code is one of the following NZ Zero flag not set Z Zero flag set NC Carry flag not set Carry flag set LZ Logical Overflow flag is not set LO Logical Overflow flag is set P Sign flag not set M Sign flag set jr e condition code is one of the following NZ Zero flag not set Z Zero flag set NC Carrv flag not set C Carrv flag set djnz e B 3 2 1 Workaround for Wait State Bug with Conditional Jumps One way to compensate for the shortened output enable signal is to add one more wait state than would otherwise be needed An example of the memory access with the shortened output enable signal is shown in the figure below chip select x X address output enable lost part of output enable signal Wait State Bug Memory Read 1 Wait State 72 rabbit com Wait State Bug B 3 3 Output Enable Signal and Mul Instruction If wait states are enabled for code memory the length of the output enable signal is reduced to a single clock cycle for the first instruction byte fetch after a multiply mu1 instruction This is the length the out put enable signal would be if there were zero wait states The read of this byte is always a long read cycle the same as 10 wait states since it is shared with the execution of mu1 Th
62. fied The uppermost bit of the 16 bit address is set to one to specify an internal I O write The remaining 15 bits specify the address If the write is to memory then the uppermost bit must be zero and the write must be to the first 32 KB of the memory space The user should see the 9 bytes transmitted at 2400 bps or 416 per bit The status bit will initially toggle fairly rapidly during the transmission of the first triplet because the default setting of the status bit is to go low on the first byte of an opcode fetch While the triplets are being read instructions are being executed from the small cold boot program within the microprocessor The status line will go low after the first trip let has been read It will go high after the second triplet is read and return to low after the third triplet is read The status line will stay low until the sequence starts again If this test fails to function it may be that the programming connector is connected improperly or the proper pull up resistors are not installed on the SMODE lines Other possibilities are that one of the oscil lators is not working or is operating at the wrong frequency or the reset could be failing Rabbit 2000 Designer s Handbook rabbit com 63 12 2 3 Diagnostic Test 2 The following program checks the processor RAM interface for an SRAM device connected to CS1 OE1 WE1 The test toggles the first 16 address lines All of the data lines must be connected to the S
63. freely meaning that the address lines from the processor can be connected in any order to the address lines of the RAM and the same applies for the data lines For example if the RAM has 15 address lines and 8 data lines it makes no difference if A15 from the processor connects to A8 on the RAM and vice versa Similarly D8 on the processor could connect to D3 on the RAM The only restriction is that all 8 processor data lines must connect to the 8 RAM data lines If several different types of RAM can be accommodated in the same PC board footprint then the upper address lines that are unused if a smaller RAM is installed must be kept in order For example if the same footprint can accept either a 128K x 8 RAM with 17 address lines or a 512K x 8 RAM with 19 address lines then address lines 18 and A19 can be interchanged with each other but not exchanged with 0 17 Permuting lines does make a difference with flash memory If the memory is socketed and it is intended to program the memory off the board then it is probably best to keep the address and data lines in their natu ral order However since the flash can be programmed in the circuit using the Rabbit programming port it is expected that most designers will solder the flash memory directly to the board in an unprogrammed state In this case the permeation of data and address lines must still be taken into account because flash memory requires the use of a special unlock code that removes
64. g a lot of data in flash mem ory another flash memory chip can be added creating a system with three memory chips two flash memory chips and one RAM chip Trying to use a single flash memory chip to store both the user s program and live data that must be fre quently changed can create software problems When data are written to a small sector flash memory the memory becomes inoperative during the 5 ms or so that it takes to write a sector If the same memory chip is used to hold data and the program then the execution of code must cease during this write time The 5 ms is timed out by a small routine executing from root RAM while system interrupts are disabled effec tively freezing the system for 5 ms The 5 ms lockup period can seriously affect real time operation 5 2 Memory Segments From the point of view of a Dynamic C programmer there are a number of different uses of memory Each memory use occupies a different segment in the logical 16 bit address space The four segments are shown here Figure 5 1 Memory Map of 16 bit Addressing Space 1 MB Quandrant 3 Extended Memory Quadrant 2 Segment Data Quadrant 1 Segment Base Segment aka Root Segment Quadrant 0 0 KB Logical Address Space Physical Address Space Figure 5 1 shows that the Rabbit does not have a flat memory space The advantage of the Rabbit s mem ory organization is that the use of 16 bit addresses and pointers is retained
65. gh This causes the Rabbit to enter the cold boot mode after reset Dynamic C can cold boot the Rabbit based target system with no pre existing program installed in the tar get The flash memory on the target system can be blank or it may contain any data The cold boot capabil ity permits the use of soldered in flash memory on the target Soldered in memory eliminates sockets boot blocks and prom programming devices However it is important that the flash memory have its software data protection enabled before it is soldered in 4 1 How the Cold Boot Mode Works In Detail The microprocessor starts executing 12 byte program contained in an internal ROM The program tains the following code Origin zero 00 1 n n20cOh for serial port A n 020h for parallel slave port 02 ioi ld hl get address most significant byte 04 ioi Id e hi get least significant bvte 06 ld a hl get data h is ignored 08 ioi or nop if D 7 1 ioi else nop 09 1 de A Store in memory or I O 10 jr O jump back to zero note wait states inserted at bytes 3 5 and 7 waiting for serial port or parallel port ready The contents of the boot ROM vary depending on the settings of the pins SMODEO and SMODEI and on the contents of register D bit 7 which determines if the store is to be an store or a data store If the boot is terminated by storing 0x80 to I O register 0x24 then when the boot program reaches address
66. h a M M we 3e el segsize reg d3 32 13 00 data seg starts at 1000h 3e 3f dataseg reg d3 32 12 00 set data seg base of flash to 1000h 00 for MBICR memory bank reg for flash on CSO 32 15 00 bank 1 reads flash starting at 256k 3e aa 32 55 65 first byte of unlock code 3e 55 32 aa 3a 2nd byte of unlock code 3e a0 32 55 65 3rd byte of unlock code 2100 10 point to start of flash memory 36 c3 jump op code 23 36 00 zero 23 36 00 zero 18 fe end with endless loop This code can be sent by means of a sequence of triplets via the serial port 80 00 00 00 00 00 00 continue code above here 14 00 01 02 03 04 05 01 1 32 12 00 00 2b 18 00 2 80 24 80 write 01 to 0000 MBOCR select csl map RAM to QI write to memory address 0 last instruction last byte start execution of program at zero The program will execute within about 10 ms 10 rabbit com Core Design and Components 3 3 PC Board Layout and Memory Permutation To use the PC board real estate efficiently it is recommended that the address and data lines to memory be permuted to minimize the use of PC board resources By permuting the lines the need to have lines cross over each other on the PC board is reduced saving feed through s and space For static RAM address and data lines can be permuted
67. hen yourcode is full For data regions the data that would overflow the region is moved to the region that follows Combined data and code regions like rcodorg use both methods which one is used depends on whether code or data caused the region to overflow In our example if data caused yourcode to overflow the data would be written to the memory region identified by mycode Furthermore a follow expression may specify that when the code or data resumes at the next region it should generate a separate bin file This option is designed to support burning multiple flash or EPROM devices The binary files generated share the same base name as the original file but appended with a number which is followed by the bin extension For example if hello c a large program that spans both flash chips is compiled to file with the splitbin option hellol binandhello2 bin will be generated Obviously this option is only meaningful when compiling to a file The optional debug expression is only valid with the xcodorg origin type It tells the compiler to gener ate only debug or nodebug code in that physical memory region If debug expression is not specified the declaration is treated as an a11 region An a11 region can have both debug and nodebug code Activating an a11 region by using apply or resume will cause both debug and nodebug regions to become inactive If an a11 region is active both debug and nodebug regions must be made active to entirely
68. is effectively precludes the use of mul with wait states unless the following condition is met the length of time from the start of the out put enable signal to when the data becomes ready to sample is less than 1 clock cycle 9 nanoseconds If the clock doubler is used alternate clocks may have slightly different lengths and a slightly stricter stan dard may need to be applied B 3 4 Alternatives to Wait States in Code Memory If the code memory is slow and requires wait states at a certain clock speed the simplest alternative is to lower the clock speed so that no wait states will be required Lowering the clock speed to 2 3 of its previ ous value has the same effect as adding one wait state Lowering the clock speed to 1 2 is the same as 2 wait states Lowering the clock speed to 1 3 is the same as 4 wait states The clock speed can be cut in half by turning of the clock doubler The clock speed can be divided by 8 by enabling the clock divider Another way to avoid wait states 1 to run normally with the clock doubler enabled and when you need to execute code from the slower memory turn off the clock doubler This doubles the length of the memory cycle which is equivalent to adding 2 wait states B 4 Enabling Wait States Memory wait states can be specified independently for each of 4 different addressing zones in the memory space The four memory bank control registers MBxCR control the wait states inserted for memory accesses in each z
69. is frequently changed by the user s code The BIOS sets up an initial value All together there are 11 MMU and MIU registers that are set up by the BIOS These registers determine all aspects of the hardware setup of the memory In addition a number of origin declarations are made in the BIOS to tell the Dynamic C compiler where to place different types of code and data The compiler maintains a number of assembly counters that it uses to place or allocate root code extended code data constants data variables and extended data variables Each of these counters has a starting location and a block size 30 rabbit com The Rabbit BIOS 6 2 BIOS Flowchart The following flowchart summarizes the functionality of the BIOS Figure 6 1 BIOS Flowchart Start at Application address 0 Program m Copy BIOS to BIOS services Yes flash Clear flag for user appli BIOS dae P in source code cation program No Setup memory control and basic BIOS ser 4 vices Start Dynamic Is the program communications Yes and state ming cable con nected machine Divert to BIOS 188 service Act as mas Service diag ter for clon nostic port ing not yet Call user appli available cation program main Rabbit 2000 Designer s Handbook rabbit com 6 3 Internally Defined Macros
70. it logical address second constant expression of physical address The size of the memory region is determined by 20 bit size Overflow of these three values is trun cated In the pre 7 05 syntax these three values are segment value logical address gt and S1ze The keywords apply and resume are action expressions They tell the compiler to generate code or data in the memory region specified by identifier An apply action resets the code or data pointer for the speci fied region to the starting physical address of the region and makes the region active A resume action does not reset the code or data pointer but does make the memory region active A region remains active 1 e the compiler will continue to generate code or data to it until another region of the same origin type is activated with an apply or resume action or until the memory region is full The option follow expression is best described with an example First let us declare yourcode in an ori gin statement containing an origin declaration A follow expression can only name a region that has already been declared in an origin declaration rcodorg yourcode 0x0 0x5000 0x500 then the origin statement rcodorg mycode 0 0 0x5500 0x500 follows yourcode tells the compiler to activate mycode when yourcode is full This action does an implicit resume on the memory region identified by yourcode In this example the implicit resume also generates a jump to mycode w
71. l operate with 70 ns memories If the maximum performance is required then a 29 4912 MHz crystal or resonator for a crystal this must be the first over tone and may need to be special ordered or a 29 4912 MHz external oscillator can be used A 29 4912 MHz system will require 55 ns memory access time table of timing specification is contained in the Rabbit 2000 Microprocessor User s Manual 4 rabbit com Rabbit Hardware Design Overview 2 3 Power Consumption When minimum power consumption is required a 3 3 V power supply and a 3 6864 MHz or a 1 8432 MHz crystal will usually be good choices Such a system can operate at the main 3 6864 MHz or 1 8432 MHz frequency either doubled or divided by 8 or both A further reduction in power consumption at the expense of computing speed can be obtained by adding memory wait states Operating at 3 6864 MHz such a system will draw approximately 11 mA at 3 3 V not including the power required by the memory Approximately 2 mA is used for the oscillator and 9 mA is used for the processor Reducing the processor frequency will reduce current proportionally At 1 4th the frequency or 0 92 MHz the current consump tion will be approximately 4 At 1 8th the frequency 0 46 MHz the total power consumption will be approximately 3 mA not including the memories Doubling the frequency to 7 37 MHz will increase the current to approximately 20 mA If the main oscillator is turned off and the microproces
72. least 128K bytes of storage to the proces sor using CSO0 OEO and 0 Non approved memories can be used but it may be necessary to mod ify the BIOS Some systems designed to have their program reloaded by an external agent on each powerup may not need any flash memory e Install a crystal or oscillator with a frequency of 32 768 kHz to drive the battery backable clock Bat tery backing is optional but the clock is used in the cold boot sequence to generate a known baud rate Install a crystal or oscillator for the main processor clock that is a multiple of 614 4 kHz or better a multiple of 1 8432 MHz These preferred clock frequencies make possible the generation of sensible baud rates If the crystal frequency is a multiple of 614 4 kHz then the same multiples of the 19 200 bps baud rate are achievable Common crystal frequencies to use are 3 6864 7 3728 11 0592 or 14 7456 MHz or double these frequencies e Digital I O line PB1 should not be used in the design if cloning is to be used See BIOS Support for Program Cloning on page 45 for more information on cloning 2 1 1 Rabbit Programming Connector The user may be concerned that the requirement for a programming connector places added cost overhead on the design The overhead is very small less than 0 25 for components and board space that could be eliminated 1f the programming connector were not made a part of the system The programming connector can also be us
73. n origin declaration origin declaration phvsical address size follow expression action expression debug expression origin type rcodorg xcodorg wcodorg rvarorg follow expression follows identifier Isplitbin action expression resume apply debug expression debug nodebug 11 size constant expression physical address constant expression constant expression The non terminals identifier and constant expressions are defined in the ANSI C specification 6 5 2 Origin Statement Semantics An origin statement associates a code pointer and a memory region with a particular type of code The type of code is specified by origin type Table 6 1 Origin types recognized by the compiler Origin Type Keyword root code rcodorg xmem code xcodorg watch code wcodorg root data rvarorg 34 rabbit com The Rabbit BIOS code sections rcodorg xcodorg code and wcodorg grow up non constant data sections rvarorg grow down Root constants are generated to the rcodorg region xdata and xstring are generated to the current xcodorg region All origin statements must have a unique ANSI C identifier The scope of this identifier is only with other origin statements or declarations In the pre 7 05 syntax this is the corigin name gt Each memory region is defined by calculating a physical address from an 8 bit base address first constant expression of physical address and a 16 b
74. nd an error 2 is returned The ID block size SIZE is determined from the first 4 bytes of the 16 byte buffer A block of bytes containing all fields from the start of the Sys IDBlock struct up to but not including the reserved field is read from flash at address 0x40000 SIZE essentially filling the SysIDBlock struct except for the reserved field since the top 16 bytes have been read earlier The CRC field is saved in a local variable then set to 0x0000 A CRC check is then calculated for the entire ID block except the reserved field and compared to the saved value If they do not match the block is considered invalid and an error 3 is returned The CRC field is then restored The reserved field is avoided in the CRC check since its size may vary depending on the size of the ID block Table 7 1 The System ID Block Babe d un Size bytes Description 00h 2 ID block version number 02h 2 Product ID 04h 2 Vendor ID 06h 7 Timestamp Y Y MM D H M S 4 Flash ID 11h 2 Flash size in 1000h pages 13h 2 Flash sector size in bytes 15h 2 Number of sectors in flash 17h 2 Flash access time nanoseconds 19h 4 Flash ID 2nd flash 1Dh 2 Flash size in 1000h pages 2nd flash 1Fh 2 Flash sector size 2nd flash in bytes 21h 2 Number of sectors in 2nd flash 23h 2 Flash access time nanoseconds 2nd flash 25h 4 RAM ID 29h 2 RAM size in 1000h pages 2
75. ng Your Own Flash Driver If a user wishes to install a flash memory that cannot be supported by following the steps in the above sec tion for example if it uses a completely different unlock write sequence two functions need to be rewrit ten for the new flash This section explains the requirements of these two functions _InitFlashDriver and WriteFlash They will need to replaced in the library that implements the flash driver FLASHWR LIB Below is the C struct used by the flash driver to hold the required information about the flash memory installed The InitFlashDriver function is called early in the BIOS to fill this struct before any accesses to the flash struct char flashXPC XPC required to access flash via XMEM int sectorSize byte size of one flash memory sector int numSectors number of sectors on flash char writeMode write method used by the flash void eraseChipPtr pointer to erase chip function in RAM eraseChipPtr is currently unused void writePtr ptr to write flash sector function RAM FlashInfo The field 1ashXPC contains the XPC required to access the first flash physical memory location via XMEM address E000h The pointer writePtr should point to a function in RAM to avoid accessing the flash memory while working with it You will probably be required to copy the function from flash to a RAM buffer in the flash initialization sequence The field wr iteMode specifies the method that
76. ning Status times per second then pause then four more flashes Dynamic C Version Cloning is active Cloning successfully completed Error occurred LED will blink quickly in a Up thru 7 06 LED blinks several distinctive pattern of four flashes PED stops 7 05 thru 7 10 in fast cloning mode LED is off LED is on LED starts blinking Starting with 7 20 LED toggles on and off about once per second LED stays on LED starts blinking 8 3 Cloning Questions The following sections answer questions about different aspects of cloning 8 3 1 MAC Address Some Ethernet enabled boards do not have the EEPROM with the MAC address namely the RCM 2100 the RCM 2200 and the BL2000 These boards can still be used as a clone because the MAC address is in the system ID block and this structure is shipped on the board and is not overwritten by cloning unless CLONE WHOLE FLASH and CL INCLUDE ID BLOCKS are both set to one Prior to Dynamic 7 20 the option to overwrite the systemID block did not exist If however you have a custom designed board that does not have the EEPROM or the system ID block you may download a program at http www rabbit com support feature downloads html to write the system ID block which contains the MAC address to your board Rabbit 2000 Designer s Handbook rabbit com 47 8 3 2 Differ
77. nization The Rabbit architecture is derived from the original Z80 microprocessor The original Z80 instruction set used 16 bit addresses to address a 64K memory space All code and data had to fit in this 64K space The Rabbit adopts a scheme similar to that used by the Z180 to expand the available memory space The 64K space is divided into zones and a memory mapping unit or MMU maps each zone to a block in a larger memory the larger memory is 1 in the case of the Z180 or the Rabbit 2000 The zones are effectively windows to the larger memory The view from the window can be adjusted so that the window looks at dif ferent blocks in the larger memory Figure 5 1 on page 24 shows the memory mapping schematically 5 1 Physical Memory The Rabbit has a 1MB physical memory space In special circumstances more than 1 of memory can be installed and accessed using auxiliary memory mapping schemes Typical Rabbit systems have two types of physical memory flash memory and static RAM memory Flash memory follows a write once in a while and read frequently model Depending on the particular type of flash used the flash memory will wear out after it has been written approximately 10 000 to 100 000 times 5 1 1 Flash Memory Flash memory in a Rabbit based system may be small sector type or large sector type Small sector mem ory typically has sectors of 128 to 1024 bytes Individual sectors may be separately erased and written In large sector memory
78. nly board work 10 1 1 Hardware Changes Ordinarily 50 OEO and WEO of the Rabbit processor are connected to a flash chip and CS1 OE1 and WEI are connected to RAM However if only RAM is to be used 50 0 and WEO must be Rabbit 2000 Designer s Handbook rabbit com 53 connected the RAM This is because on power up or reset the Rabbit will begin fetching instructions from whatever is hooked up to CSO 0 and 10 1 2 Software Changes To program a RAM only board with Dynamic C or the Rabbit Field Utility RFU several changes are needed When Dynamic C or the RFU first start they put the Rabbit based target board in bootstrap mode where it awaits data sent via triplets These programs then send triplets that map the lowest quadrant of physical memory to CS1 OE1 and WEI to load a primary loader to RAM The first set of triplets loaded to the target is contained in a file called coldload bin A different coldload bin is required in order to map the lowest memory quadrant to CSO 0 and WEO The image file for this program is NBIOSNRAMONLYCOLDLOAD BIN To use it rename BIOSNCOLDLOAD BIN to BIOSNCOLD LOAD BAK and rename NBIOSNRAMONLYCOLDLOAD BIN to BIOS COLDLOAD BIN Later ver sions of Dynamic C may have a GUI method of choosing the cold loader The primary loader loads a secondary loader which doesn t affect the memory mapping The secondary loader loads the Rabbit BIOS to RAM from the
79. nnecessary for the user to understand or work out the details of the memory setup and other processor initialization Rabbit 2000 Designer s Handbook rabbit com 29 6 1 Startup Conditions Set Up By the BIOS The BIOS sets up initial values for the following registers by means of code and declarations The four memory bank control registers MBOCR MB1CR MB2CR and MB3 CR are 8 bit registers each associated with one quadrant of the 1M memory space Each register determines which memory chip will be mapped into its quadrant how many wait states will be used for accessing that memory chip and whether the memory chip will be write protected The STACKSEG register is an 8 bit register that determines the location of the stack segment in the 1M memory The DATASEG register is an 8 bit register that determines the location of the data segment in the 1M memory normally the location of the data variable space The SEGSIZE register is an 8 bit register holding two 4 bit registers Together the registers determine the relative size of the base segment data segment and stack segment in the 64K root space The MMIDR register is an 8 bit register used to force CS1 to be always enabled or not Having CS1 always enabled reduces power consumption The XPC register is used to address extended memory Normally the user s code frequently changes this register The BIOS sets the initial value The SP register is the system stack pointer It
80. ns it will skip step 12 It also modifies a byte near the beginning of the program where it stores the baud rate divider to achieve 19200 baud This constant is used by the serial communications initializa tion library functions to compute baud rate dividers 12 The BIOS copies itself to flash at 0x80000 and switches the mapping of flash and RAM so that RAM is at 0x80000 and flash is at 0x00000 As soon as this remapping is done the BIOS execution of instructions begins happening in flash 13 Dynamic C is now ready to compile a user program When the user compiles his program to the target it is first written to a file then the file is loaded to the target using the BIOS FSM The file is used as an intermediate step because fix ups are done after the compilation is complete and all unknown addresses are resolved The fix ups would cause extra wear on the flash if done straight to the flash 14 When the program is fully loaded Dynamic C sets a breakpoint at the beginning of main and runs the program up to the breakpoint The board has been programmed and Dynamic C is now in debug mode 15 If the programming cable is removed and the target board is reset the user s program will start running automatically because the BIOS will check the SMODE pins to determine whether to run the user application or enter the debug kernel 22 rabbit com How Dynamic C Cold Boots the Target System Semiconductor Chapter 5 Rabbit Memory Orga
81. of Moda Time Voltage amosa C Version bytes bytes Sectors ns V Atmel AT29C1024 64K 128 512 sector 70 4 5 5 5 5 6 7 025 Atmel AT29LV1024 64K 128 512 sector 150 3 0 3 6 5 6 7 025 Atmel AT29C010 128K 128 1024 sector 70 4 5 5 5 1 2 4 Atmel AT29LV010 128K 128 1024 sector 150 3 0 3 6 2 4 All Atmel AT29BV010 128K 128 1024 sector 200 2 7 3 6 2 4 7 025 Atmel AT29C020 256K 256 1024 sector 70 4 5 5 5 1 2 4 6 50 Atmel AT29LV020 256 256 1024 sector 200 3 0 3 6 2 4 6 50 Atmel AT29BV020 256K 256 1024 sector 250 2 7 3 6 2 4 7 025 Atmel AT29C040 512K 256 2048 sector 120 4 5 5 5 1 4 6 576 Atmel AT29LV040 512 1256 2048 sector 200 3 0 3 6 4 6 576 Atmel AT29BV040 512K 256 2048 sector 200 2 7 3 6 4 6 570 Mosel Vitelic 29 51001 128K 512 256 45 4 5 5 5 1 2 4 6 50 Mosel Vitelic V29LC51001 128K 512 1256 byte 90 4 5 5 5 1 2 7 026 Mosel Vitelic 29 51002 256K 512 512 byte 55 4 5 5 5 1 2 4 6 50 Mosel Vitelic V29LC51002 256K 512 512 byte 90 4 5 5 5 1 2 7 026 Mosel Vitelic V29C51004 512K 1024 512 byte 70 4 5 5 5 2 4 6 576 Mosel Vitelic V29C31004 512K 1024 512 byte 90 3 0 3 6 2 4 7 026 SST SST29EE512 64K 128 512 sector 70 4 5 5 5 1 2 3 4 6 50 SST SST29LESI2 64K 128 512 sector 150 3 0 3 6 1 2 3 4 6 50 Rabbit 2000 Designer s Handbook rabbit com 55 Table 11 1 32 Pin Flash Memories Supported by the Rabbit 2000 Small Sector
82. old boot the target system by resetting it and downloading a primary boot program The master then sends the entire BIOS over to the clone where the boot program receives it and stores it in RAM just like Dynamic C does when compiling the BIOS A CRC check of the BIOS is performed on both the master and clone and the results are compared The clone is reset again and the BIOS on the clone begins running Finally the master sends the user s program at high speed and the program is writ ten to the flash memory When the designated portion of the flash has been transferred the clone flashes the cable LED in a distinc tive pattern to indicate that the programming is done At that point the cloning board can be unplugged and plugged into another target When the master is reset it will program the next clone Rabbit 2000 Designer s Handbook rabbit com 45 8 1 1 Evolution of Cloning Support Over several versions of Dynamic C cloning has improved in terms of data transfer rates and options that may be set in the BIOS Dynamic C mm f Clonin Version Summary of Cloning Support 6 50 Initial cloning support added Data transfer rates of 57 600 bps or 115 200 bps available 7 05 Fast cloning introduced with restrictions Maximum data transfer rates determined by the crystal frequency Only fast cloning is available Fast cloning restrictions 7 20 removed More options introduced For details on both the
83. one The number of wait states can be programmed as 0 1 2 or 4 The principle reasons for enabling memory wait states are 1 During startup of the Rabbit 2000 wait states are automatically set to 4 wait states Unless it has been modified the BIOS promptly sets the processor to zero wait states 2 Enabling wait states can be used as a strategy for reducing power consumption This can still be done if the restrictions and work arounds detailed in this chapter are adhered to For example you don t use the 20 instructions that execute incorrectly 3 A slow flash memory used for data storage may be interfaced to the processor as a memory device and it may require wait states This will still work as long as only data accesses are made to the memory If instructions are to be executed from the memory then the restrictions and work arounds detailed in this chapter must be adhered to Rabbit 2000 Designer s Handbook rabbit com 73 5 In a typical design implementation wait states are not used for access to the main instruction memory Normally the processor clock speed is selected so that with zero wait states the processor memory cycle is matched with the instruction memory access time Hence the wait state bug will not be encountered by most users If the memory used is fast enough to run at zero wait states and the 20 failing instructions are not used then inserting wait states will not cause problems Thus when the
84. play the progress of the transfer 2 1 3 Oscillator Crystals Generally a system will have two oscillator crystals a 32 768 kHz crystal to drive the battery backable timer and another crystal that has a frequency that is a multiple of 1 8432 MHz or a multiple of 3 6864 MHz Typical values are 1 8432 3 6864 7 3728 11 0592 14 7456 18 432 25 8048 and 29 4912 MHz These crystal frequencies except 1 8432 MHz allow generation of standard baud rates up to at least 115 200 bps The clock frequency can be doubled by an on chip clock doubler but the doubler should not be used to achieve frequencies higher than about 22 1184 MHz on a 5 V system and 14 7456 MHz on a 3 3 V system A quartz crystal should be used for the 32 768 kHz oscillator For the main oscillator a ceramic resonator accurate to 0 596 will usually be adequate and less expensive than a quartz crystal 2 2 Operating Voltages The operating voltage in Rabbit based systems will usually be 5 V or 3 3 V but 2 7 V is also a possibility The maximum computation per watt is obtained in the range of 3 0 V to 3 6 V The highest clock speeds require 5 V The maximum clock speed with a 3 3 V supply is 18 9 MHz but it will usually be convenient to use a 7 3728 MHz crystal doubling the frequency to 14 7456 MHz Good computational performance but not the absolute maximum can be implemented for 5 V systems by using an 11 0592 MHz crystal and doubling the frequency to 22 1184 MHz Such a system wil
85. puts by proper software initialization to remove the floating property Pullup resistors will be needed on a few inputs that cannot be programmed as outputs An alter native to a pullup resistor is to tie an unused output to the unused inputs If pullup or pulldown resistors are required they should be made as large as possible if the circuit in question has a substantial part of its duty cycle with current flowing through the resistor Rabbit 2000 Designer s Handbook rabbit com 49 Figure 9 1 Rabbit Clock Distribution Rabbit 2000 f 2__ ext pin 92 CLK disable Clock CPU Oscillator Doubler Peripheral Devices Oscillator 32 kHz watchdog timer time date clock Note Peripherals cannot be clocked slower than the CPU For extreme low power operation take into account that some memory chips draw substantial current at zero frequency For example a Samsung static RAM part number KM684000BPL 7L was found to draw 1 mA at 5 V when chip select and output enable were held enabled and all the other signals were held at fixed levels a long read When the microprocessor is operating at the slowest frequency 32 kHz clock the memory cycle is about 64 us and the memory chip spends most of its time with the chip enable and output enable on The current dra
86. r in bytes int numSectors number of sectors int flashSpeed in nanoseconds long flash2ID Rabbit part 2nd flash int flash2Type Write method 2nd flash int flash2Size in 0x1000 pages 2nd flash int sector2Size byte size of 2nd flash s sectors int num2Sectors number of sectors int flash2Speed in nanoseconds 2nd flash long ramID Rabbit part int ramSize in 0 1000 pages int ramSpeed in nanoseconds int cpuID CPU type identification long crystalFreq in Hertz char macAddr 6 Media Access Control MAC address char serialNumber 24 device serial number char productName 30 NULL terminated string char reserved 1 reserved for later use size can grow long idBlockSize size of the SysIDBlock struct int userBlockSize size of user block directly below SysID block int userBlockLoc offset of start of user block from this block int idBlockCRC CRC of this block when this field is set to zero char marker 6 should be 0x55 OxAA 0x55 OxAA 0 55 OxAA SysIDBlock 40 rabbit com The System ID Block 7 2 Access The BIOS will read the system ID block during startup so all a user needs to do is access the system ID block struct Sys IDBlock in memory If the BIOS does not find an ID block it sets all parameters in SySIDBlock to zero 7 2 1 Reading the System ID Block To read the system ID block the following function from IDBLOCK L
87. re considered EMI refers to unintentional radia tion from the circuit board that might cause interference with other devices mainly television sets If the PCB layout meets EMI regulations it will probably be otherwise electrically sound 3 4 1 EMI Regulations The Federal Communications Commission FCC regulates EMI standards in the United States Their jurisdiction is all 50 states the District of Columbia and U S possessions The European Union EU reg ulates EMI standards in Europe by means of a CE Marking that acts as a product s passport in the Euro pean market The actual CE Marking is the letters CE an abbreviation of a French phrase Conformite Europeene These regulations specify the maximum radiation measured in units of field strength microvolts meter at a standard distance usually 3 meters The field strength must be measured using a particular type of fil ter 120 kHz wide and a particular type of peak detection quasi peak With Rabbit based systems the radiation will generally be pure tones at harmonics of the clock speed This makes it unnecessary to use a special filter or quasi peak detection except for final verification measurements 3 4 1 1 EMI Measuring Devices The measurements are performed using a spectrum analyzer coupled to a calibrated antenna The equip ment needed to perform these tests may cost 25 000 or more Many designers will use outside laborato ries to perform the tests There is not ne
88. ry wait states can further slow the processor to about 500 instructions per second or one every 2 ms At these speeds the power consumed by the microprocessor exclusive of the 32 768 kHz oscillator is very low in the area of 50 pA to 100 pA The Rabbit will generally test for some external event and leave sleepy mode when that event is detected The 32 768 kHz oscillator is a major consumer of power requiring approximately 80 uA at 3 3 V This drops dramatically to about 18 uA at 2 2 V For the lowest standby power it may be desirable to use an external oscillator to generate the 32 768 50 rabbit com Low Power Design and Support kHz clock The Intersil formerly Harris part HA7210 can be used to construct 32 768 kHz oscillator that consumes approximately 5 uA at 3 3 V For the very lowest power consumption the processor can execute a long string of mul instructions with the de and bc registers set to zero Few if any internal registers change during the execution of a string of mul zero by zero and a memory cycle takes place only once in every 12 clocks By combining all these techniques it may be possible to get the sleepy current under 50 pA Rabbit 2000 Designer s Handbook rabbit com 51 9 1 Software Support for Low Power Sleepy Modes In sleepy mode the microprocessor executes instructions too slowly to support most interrupts The serial ports can function but cannot generate standard baud rates since the system clock is at 32 768
89. s 2 0 63 12 2 3 Diagnostic Test 82 n nin dae HH nats pe Re Nerva a v e D ERR 64 Supported Rabbit 2000 Baud 67 B Wait BUS iam 69 Bil Overview dug dpi B p sa 69 2 Wait States In Data Memloty utei dnte 69 B 3 Wait States in Code 70 B 3 1 Instructions Affected by the Wait State Bug 70 B 3 1 1 Dynamic C Version 7 05 cast 71 3 1 2 Prior versions of etai ie inei ey 71 B 3 2 Output Enable Signal and Conditional Jumps 72 B 3 2 1 Workaround for Wait State Bug with Conditional Jumps 72 B 3 3 Output Enable Signal and Mul Instruction nennen 73 B 3 4 Alternatives to Wait States in Code Memory sess 73 IBA Enabling Wait a 73 lint T H 74 hri E 75 Rabbit 2000 Designer s Handbookl rabbit com vi rabbit com Table of Contents Semiconductor Chapter 1 Introduction This manual is intended for the engineer designing a system using the Rabbit microprocessor and the Dynamic C development environm
90. s suited for your unique board design 62 rabbit com Troubleshooting Tips for New Rabbit Based Systems 12 2 2 Diagnostic Test 1 Toggle the Status Pin This test toggles the status pin It is available as StatusTgl Diag one of the diagnostic samples downloaded in ser io rab20 zip 1 Apply the reset for at least 4 second and then release the reset This enables the cold boot mode for asynchronous serial port A if the programming cable is connected to the target s programming connec tor 2 Send the following sequence of triplets 80 OE 20 sets status pin low 80 OE 30 sets status pin high 80 OE 20 sets status pin low again 3 Wait for approximately second and then repeat starting at step 1 While the test is running an oscilloscope can be used to observe the results The scope can be triggered by the reset line going high It should be possible to observe the data characters being transmitted on the RXA pin of the processor or the programming connector The status pin can also be observed at the processor or programming connector Each byte transmitted has 8 data bits preceded by a start bit which is low and fol lowed by a stop bit which is high viewed at the processor or programming connector The data bits are high for 1 and low for 0 The cold boot mode and the triplets sent are described in Section 4 1 Each triplet consists of a 2 byte address and a 1 byte data value The data value is stored in the address speci
91. se of memory wait states was discovered in the Rabbit 2000 processor approxi mately 13 months after the product was introduced This bug was not discovered previously because the use of wait states in situations that evoke the problem is unusual A number of modifications to Dynamic C starting with version 7 05 have been made to make it easy or in some cases automatic to avoid problems created by the bug The bug manifests when memory wait states are used during certain instruction fetches or during certain read operations The data read instructions are the simpler case and we will describe them first Wait states for I O devices work normally and are not associated with this problem B 2 Wait States In Data Memory The two instructions LDDR and LDIR are repeating instructions that move a block of data in memory If wait states are enabled then one wait state less than specified is used on every data read except the first one in the block This can be corrected in either of two ways An additional wait state can be specified which will cause there to still be sufficient wait states when one is lost or a directive can be issued to the Dynamic C compiler to automatically substitute different instruc tions for LDDR or LDIR which accomplish the same operation The directive is pragma DATAWAITSUSED on pragma DATAWAITSUSED off This will cause Dynamic C to substitute code as follows ldir becomes call ldir func and lddr becomes c
92. should be approximately 3 3 V At a given operating voltage the clock speed should be reduced as much as possible to obtain the mini mum power consumption that is acceptable Some applications such as a control loop may require a continuous amount of computational power Other applications such as slow data logging or a portable test instrument may spend long periods with low computational requirements interspersed with short periods of high computational load The current and thus power consumption of a microprocessor based system generally consists of a part that is independent of frequency and a part that depends on frequency The part that is independent of fre quency consists of leakage or current or current drawn by special circuits such as pullup resistors or cir cuits that continuously draw power Ordinary CMOS logic uses power when it is switching from one state to another and this is the power that is dependent on frequency The power drawn while switching is used to charge capacitance or is used when both N and P FETs are simultaneously on for a brief period during a transition Floating inputs or inputs that are not solidly either high or low can also draw current because both N and P FETs are turned on at the same time To avoid excessive power consumption floating inputs should not be included in a design except that some inputs may float briefly during power on sequencing Most unused inputs on the Rabbit can be made into out
93. site effect It can be changed to as low as 0x3000 or as high as 0 000 RAM SIZE This macro sets the amount of RAM available The default value is the internally defined RAM SIZE The units are the number of 4k pages of RAM In special situations such as split ting RAM between two coresident programs this may be modified to a smaller value than the ac tual available RAM FLASH SIZE This macro sets the amount of flash available The default value is the internally defined FLASH SIZE The units are the number of 4k pages of flash In special situations such as splitting flash between two coresident programs this may be modified to a smaller value than the actual available flash CS1 ALWAYS ON Keeping CSI active is useful if your system is pushing the limits of RAM access time It will in crease power consumption a little Set to 0 to disable 1 to enable WATCHCODESIZE These define the number of bytes available to the debugger for compiling watch expression The default values are 0x200 0x060 Decreasing these increases the amount of RAM available for root data NUM RAM WAITST NUM FLASH WAITST These define the number of wait states to be used for RAM and flash The default value for both is 0 The only valid values are 4 2 1 and 0 MBOCR INVRT A18 MBICR INVRT A18 MB2CR INVRT A18 MB3CR INVRT A18 MBOCR INVRT A19 MBICR INVRT A19 MB2CR INVRT A19 MB3CR INVRT A19 These determine whether the MIU registers for each quadrant are set up
94. sor is operated at 32 768 kHz from the clock oscilla tor the current will drop to about 200 uA exclusive of the current required by the memory The level of power consumption can be fine tuned by adding memory wait states which have the effect of reducing power consumption To obtain microampere level power consumption it is necessary to use auto power down flash memories to hold the executing code Standby power while the system is waiting for an event can be reduced by executing long strings of multiply zero by zero instructions Keep in mind that a Rabbit operating at 3 68 MHz has the compute power of a Z180 microprocessor operating at approximately triple the clock frequency 11 MHz 2 4 Through hole Technology Most design advice given for the Rabbit assumes the use of surface mount technology However it is pos sible to use the older through hole technology and develop a Rabbit system One can use the Rabbit based Core Module a small circuit board with a complete Rabbit core that includes memory and oscillators Another possibility is to solder the Rabbit processors by hand to the circuit board This is not difficult and is satisfactory for low production volumes if the right technique is used Rabbit 2000 Designer s Handbook rabbit com 5 rabbit com Rabbit Hardware Design Overview Semiconductor Chapter 3 Core Design and Components Core designs can be developed around the Rabbit 2000 microprocessor A core design inclu
95. the sectors are often 16K or 64K or more Small sector memory provides better sup port for program development and debugging and large sector memory is less expensive and has faster access time The best solution will usually be to lay out a design to accept several different types of flash memory including the flexible small sector memories and the fast large sector memories At the present time development support for programs tested in flash memory is confined to flash memo ries with small sectors If larger sectors are used the code must be debugged in RAM and then loaded to flash Large sector flash is desirable for the better access time and power consumption specifications that are available Dynamic C is being modified to handle large sector flash at the time of this writing 5 1 2 SRAM Static RAM memory may or may not be battery backed If it is battery backed it retains its data when power is off Static RAM chips typically used for Rabbit systems are 32K 64K 128K 256K or 512K When the memory is battery backed power is supplied at 2 V to 3 V from a backup battery The shutdown circuitry must keep the chip select line high while preserving memory contents with battery power Rabbit 2000 Designer s Handbook rabbit com 23 5 1 3 Basic Memory Configuration A basic Rabbit system has two static memory chips one flash memory chip and one RAM memory chip Additional static memory chips may be added If an application requires storin
96. this circuit the battery backed clock requires less than 25 pA If the full 3 V is used the current consumption will be approximately 70 uA Figure 3 2 Clock Oscillator Regulator Circuit 1KQ BAT3V ANN Safety resistor required by regulatory agencies 220 KQ a battery backup power 2MQ 4 3 3 1 2 Conformal Coating of 32 768 kHz Oscillator Circuit This circuit has low microampere level circuits To avoid leakage due to moisture and ionic contamination it is recommended that the oscillator circuit be conformally coated This is simplified if all components are kept on the same side of the board as the processor Feedthroughs that pass through the board and are con nected to the oscillator circuit should be covered with solder mask which will serve as a conformal coating for the back side of the board from the processor An application note on conformal coating is available from Rabbit Semiconductor 8 rabbit com Core Design and Components 3 2 Basic Memory Design Normally 80 and OEO and WEO should be connected to a flash memory that holds the startup code that executes at address zero When the processor exits reset with SMODE1 SMODE O set to 0 0 it will attempt to start executing instructions at the start of the memory connected to 50 0 and WEO By convention the basic RAM memory should be connected to CS1 OE1 and WEI CS1 has a special property that makes it the preferred chip sele
97. w during a long read cycle is not specified in most memory data sheets The Samsung chip according the data sheet typically draws about 4 mA per megahertz when it is operat ing However it appears that current consumption curve flattens out at about 250 kHz because of the con stant 1 mA draw during a long read To take full advantage of the Rabbit s ultra slow sleepy execution modes a memory that does not consume power during a static read is required Advanced Micro Devices has a line of 3 V flash memories AM29LV010 AM29LV040 that power down automatically whenever the address and control lines do not change for a period of time slightly longer than the access time These memories will consume on the order of 30 uA when operated at a data rate of 1 64 MHz Prior to version 7 10 Dynamic C did not allow debugging with flash chips having sector sizes greater than 4096 bytes nor did the flash drivers provided in the Dynamic C libraries support such flash chips To use a large sector flash in your product design if you are using a version of Dynamic C prior to 7 10 you can debug your application in RAM by using the Compile to RAM compiler option or use a board with small sector flash for development only The Rabbit low power sleepy mode of operation is achieved by switching the main clock to the 32 768 kHz clock and then disabling the main oscillator In this mode the Rabbit executes about 3 instructions every millisecond Adding memo
98. well 5 This function should return zero if successful or 1 if an error occurs Rabbit 2000 Designer s Handbook rabbit com 59 _WriteFlash This function writes exactly one sector of data from a buffer in RAM to the flash memory aligned along a flash sector boundary _WriteFlash is called from the BIOS the user will normally call higher level flash writing functions as well as several libraries and should be written to conform to the following require ments For versions of Dynamic C prior to 7 02 it should assume that the source data is located at the logical RAM address passed in BC In all later versions of Dynamic C a fixed 4096 byte block of XMEM is used for the flash buffer which can be accessed via macros located at the top of FLASHWR LIB These macros include FLASH BUF PHYS the unsigned long physical address of the buffer FLASH BUF XPCand FLASH BUF ADDR the logical address of the buffer via the XMEM window and FLASH BUF 0015 and FLASH BUF 1619 the physical address of the buffer broken down to be used with the LDP opcodes It should assume that the flash address to be written to is passed as an XMEM address in A DE The destination must be aligned with a flash memory sector boundary It should check to see whether the sector being written contains the ID or user blocks If so it should exit with an error code see below Otherwise it should perform the actual write operation required by the particular flash used
99. y backed there will be no startup delay since the oscillator is already oscillating Rabbit 2000 Designer s Handbook rabbit com 7 3 1 1 Low Power Design The power consumption is proportional to the clock frequency and to the square of the operating voltage Thus operating at 3 3 V instead of 5 V will reduce the power consumption by a factor of 10 9 25 or 43 of the power required at 5 V The clock speed is reduced proportionally to the voltage at the lower operat ing voltage Thus the clock speed at 3 3 V will be about 2 3 of the clock speed at 5 V The operating cur rent is reduced in proportion to operating voltage The Rabbit does not have a standby mode that some microprocessors have Instead the Rabbit has the ability to switch its clock to the 32 768 kHz oscillator This is called the sleepy mode When this is done the power consumption is dramatically decreased The current consumption is often reduced to the region of 100 pA at this clock speed The Rabbit executes about 6 instructions per millisecond at this low clock speed Generally when the speed is reduced to this extent the Rabbit will be in a tight polling loop looking for an event that will wake it up The clock speed is increased to wake up the Rabbit If current consumption by the real time clock RTC is important the regulator circuit shown in the figure below will reduce the current consumption by a substantial amount when a 3 V lithium battery is used Using
100. zero the boot mode is disabled and instruction fetching resumes at address zero Wait states are automatically inserted during the fetching of bytes 3 5 and 7 in order to wait for the serial or parallel port ready The wait states continue indefinitely until the serial port is ready This will cause the processor to be in the middle of an instruction fetch until the next character is ready While the processor is in this state the chip select but not the output enable will be enabled if the memory mapping registers are such as to normally enable the chip select for the boot ROM address The chip select will stay low for extended periods while the processor is waiting for the serial or parallel port data to be ready Additionally the chip select will go low when a write is performed to an I O address if the address is such as to enable that chip select if it were a write to a memory address 20 rabbit com How Dynamic C Cold Boots the Target System 4 2 Program Loading Process Overview The program loading process described here is current through Dynamic C version 7 06 On start up Dynamic C first uses the PC s DTR line on the serial port to assert the Rabbit Reset line and put the processor in cold boot mode Next Dynamic C uses a four stage process to load a user program 1 Load an initial loader cold loader via triplets sent at 2400 baud from the PC to a target in cold boot mode 2 Run the initial loader and load a secondary load

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