Project description (PDF
Contents
1. oe 10 6 5 Eu 10 6 6 10 6 7 Key Return Sigal Detection E L 10 6 8 IACI RIOTS rE UCU s EE 10 6 9 Waton 11 7 Low Power Design Considerations 11 Block Digraness 12 9 User lnterface 5 cuna ac ees eines ieee een Steet eee Ree ee 13 9 1 Se cup M 13 List of Figures Figure 1 SONY modulation sssssssssssseseseeee eene entente enses ret 4 Figure 2 SONY packet delati da det sepe us dat ee Rad a prs 5 Figure 3 PHILIPS RC 5 modulation sees eene nennen nnn entere 5 Figure 4 PHILIPS RC 5 5 Figure 6 6 Fig re 6 JVO packet iin uet eee 6 Figure 7 capture and store algorithm essere nnne tr sr enhn nennen sn siens 72. Cornelius Van Drebble Mad Design Contest BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest TABLE OF CONTENTS 1 ee oS Se eS eS ee er 3 14 Typical E a E I eae vee eae 3 eN aaae earren 3 Markets esL 3 Overview of IR remote control data transmission 4 4 1 SOMYASIRG OLOLOCON 25 4 4 2 Philips RG 5 i 5 4 3 E E 5 5 Design 6 5 1 Information capture and storage n ced ec ici ende e pea Fei ee ea Eh Ee rne Pc 6 5 2 Furthier design considerations ucc citet eset e eterne iad va tees LE na i RUE d ve E eV vea EN od rude eva 8 5 3 Design 9 6 Specific functions used the microcontroller UPD78F9835 9 6 1 E EE 9 6 2 50 Remote Control 9 6 3 40 30 operated as Carrier 9 6 4 2
3. 10 References 1 Preliminary User s Manual uPD789835 Subseries 8 Bit Single Chip Microcontrollers START STOP DEFAULT NOW SELECT PROGRAM SET DEFAULT RENAME DELETE COMMAND SET Y M D H S SAVE DISCARD LIST LIST LIST SELECT PROGRAM SAVE Document No U15559EJ1V1UDU1 1st edition revised in U S Date Published June 2002 N CP k 2 SB PROJECTS http www xs4all nl sbp knowledge ir ir htm 3 Vishay Semiconductors Data Formats for IR Remote Control Page 14 of 14 BrainlRac DEFAULT NAME USER NAME SET PLAY TIME ENTER NAME CONFIRM LIST Author Marcel Ursu
4. i Figure 5 JVC modulation 1001 1010101201 100 LSB MSBLSB MSB 4 8 Ams 4 2mo Address Command gt Figure 6 JVC packet 5 Design Considerations 5 1 Information capture and storage The BrainlRac shall capture and store the IR packets as shown in Figure 7 Capture and Store Algorithm Page 6 of 14 BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest CAPTURE amp STORE MODE NEW PACKET Y MEASURE THE TIME SINCE LAST Y PACKET o STORE THE TIME SINCE LAST PACKET Y DETECT CARRIER PARAMETERS PREVIOUSLY STORED Y STORE CARRIER PARAMETERS CAPTURE RAW PACKET AND COMPARE WITH PREVIOUS RAW PACKET PACKETS ARE IDENTICAL ENCODE amp STORE THIS PACKET AS SAME AS PREVIOUS e DETECT START STOP AND BIT ENCODING PREVIOUSLY STORED STORE START STOP AND BIT ENCODING CREATE HEADER AS REFERENCE TO CARRIER PARAMETERS START STOP AND BIT ENCODING PREVIOUSLY STORED Y STORE HEADER M STORE PACKET AS HEADER BINARY DATA Figure 7 Capture and Store Algorithm Page 7 of 14 The BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest 5 2 Further design considerations Another de
5. 0 and CR40 program carrier time t1 and t2 respectively Page 9 of 14 The BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest Register CR30 programs the carrier modulation cycle In order to achieve PWM or PDM modulation CR30 needs to be dynamically reloaded with the proper values Servicing the interrupt generated by TM30 INTTM30 can accomplish this TM40 input clock f or 4 f x depending on the values of carrier parameters t1 t2 and the maximum acceptable error of generating them 30 input clock TM40 output clock 6 4 Serial Interface Used primarily to program the microcontroller internal flash memory An external multiplexer allows connection of a serial RTC real time clock and a 3 wire serial flash memory for program memory expansion 6 5 8 bit ADC The 8 bit A D converter is used to monitor the Vdd microcontroller supply voltage Vdd is compared with a reference voltage Vref 2 048V input on channel ANIO From microcontroller electrical specifications Vdd 3 0V lt Vdd lt 3 6V Vno Vier 2 048V Vdd 2 where N is the ADC conversion result Therefore N should be in the range Vdd ref max 25 lt N lt V Vdd 2 ref To save energy ADC conversion is started once every 5s when Vdd is in a 300mV middle range between Vdd and ADC conversion rate is increased as Vdd gets closer to the extremes An alarm is raised when N go
6. ET1 PWM BIT ENCODING MANCHESTER PDM CARRIER 1 CARRIER 2 CARRIER PARAMETERS CARRIER N START STOP 1 START STOP2 PACKET 1 START STOP PARAMETERS START STOPN HEADER 1 HEADER 1 DATA HEADER 2 PACKET 2 TIME 1 RUN LENGTH HEADER N HEADER 1 DATA ENCODED PROGRAM ABC BEGIN TIME PROGRAM ABC END COUNT PROGRAM XYZ BEGIN PROGRAM XYZ END TIME N HEADER 2 DATA Figure 9 Data Store 5 3 Design Implementation The BrainlRac shall use the UPD78F9835 microcontroller The main system clock shall run at 5MHz The subsystem clock shall run at 32 768kHz 6 Specific functions used in the microcontroller UPD78F9835 6 1 LCD Interface Configured as 80x16 and used to drive an LCD display of 16 characters x 2 rows Each character is 8x5 dots 6 2 TM50 Remote Control Timer The 8 bit remote control timer 50 has a pulse width measurement function with a resolution of 8 bits It has rising falling edge detection circuitry Carrier t1 and t2 time count is captured in registers CP50 and CP51 respectively with minimal CPU intervention 50 input clock Y f 2 5MHz or a period of 0 45 6 3 TM40 TM30 operated as Carrier Generator An arbitrary carrier clock generated by TM4O is output the cycle set in TM30 Registers CRH4
7. Figure 8 Carrier 8 9 Data Store m 9 Figure 10 Block 2211 a 13 Figure 11 User MO 14 Page 2 of 14 BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest 1 Description The device we propose called The BrainlRac is designed to capture store and transmit multiple infrared IR command sequences It greatly simplifies and speeds up control of various IR devices like TV DVD CD etc The BrainlRac can be described by analogy with some computer programs like MS EXCEL or ORCAD schematic capture whereby the user is able to capture and save a sequence of keystrokes as a macro That macro can then be run as needed The aim is obviously to automate and speed up repetitive tasks 1 1 Typical Applications 1 Home theatre system TV DVD CD Receiver Set top box automatic turn ON OFF and set to initial state source channel selection amplifier volume using the original remote with the push of one button only 2 In store Audio Video equipment demo 3 Home Security occupancy simulation through Audio Video use 4 Parental control TV control based on time of day 5 Party CD changer and amplifier volume control 2 Features 1 Able to capture commands transmitted by virtually any consumer electronics infrared remot
8. benefit is that the time count will not be lost when the main batteries run out and need to be replaced The processor will exit this ultra low power mode with an external interrupt such as RTC alarm or any user key Another solution to this design issue is to use the mask ROM version of this microcontroller This would allow using the internal Watch Timer without the penalty of high current draw and thus remove the need for an external RTC It is a lower cost solution but less flexible more suitable for high volume production runs Page 11 of 14 The BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest 8 Block Diagram IR X RECEIVER ANALOG FRONTEND X VDD VREF IR A TRANSMIT BUFFER 2 048V PROGRAMMING INTERFACE MULTIPLEXER m INA OUT A RTC REAL TIME CLOCK ALARM r CLK B m IN B 4 OUT B SELECT GREEN KE LCD 16 CHARS X 2 ROWS VDD RESET GENERATOR Page 12 of 14 UPD78F9835 TM50 REMOTE CONTROL TIMER CARRIER TM40 TM30 GENERATION SERIAL INTERFACE SOUND GENERATOR LCD BOOSTER LCD INTERFACE BrainlRac AMPLIFIER BUZZER Author Marcel Ursu Cornelius Van Drebble Mad Design Contest Figure 10 Block Diagram 9 User Interface T
9. e control IRRC 2 Able to store a sequence of commands with relative time stamps as a program 3 Able to store and manage multiple programs 4 Able to schedule and trigger execution of any stored program In this context execution of a program means transmitting the sequence of commands that make up the program 5 A program trigger is defined as a time point or a stored IR command 6 User interface based on LCD LED push buttons IR commands and audio tones 7 Able to detect and signal the battery low condition 3 Markets Due to its flexibility it can address several different markets 1 Domestic use to extend and augment IR control usage scenarios For example a DVD ON macro would have the TV DVD and the amplifier all turned on and preset in one sequence initiated by pushing only one button on the original remote Similarly a CD macro would control the CD changer and the amplifier 2 Security i e occupancy simulation through audio video equipment use For example all IR commands could be captured during actual TV watching time for say 2 hours Then this macro could be saved and be run on specific days and preset time 3 Electronics Retail automatically exercise any IR controlled product for demo purposes Page 3 of 14 The BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest For example all IR commands could be captured during an actual demo for say the XYZ TV set Then t
10. es within 5 of the valid range 6 6 Sound Generator It is used to convey a battery low warning and to confirm key pressing The sound generator is programmable and can generate 16 volume levels and different frequencies 6 7 Key Return Signal Detection This function generates an interrupt INTKROO upon detecting a falling edge on any of the KROO to port lines Four user interface keys are connected KROO to KROS3 The ISR interrupt service routine reads the input port KROO to KRO3 to detect the active key 6 8 Multiplier Function The multiplier has the following function Calculation of 8 bits x 8 bits 16 bits Page 10 of 14 The BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest This function just might be needed if it turns out that further digital filtering at carrier reception is required Most IR receivers are built to accommodate one or a few closely related protocols The implication is that the carrier frequencies are the same or very close This in turn allows for BPF band pass filtering centered on the carrier frequency to be built into the IR analog frontend Because BrainlRac must be able to accommodate a wide carrier frequency range 25kHz to 80 kHz so it cannot use an IR frontend with built in BPF Depending on the characteristics and the quality of that IR frontend digital filtering may be required to filter out the noise A way around this issue may be to use multiple s
11. he user interacts with The BrainlRac through an Interface that is made up of One LCD panel of 16 characters x 2 rows Four keys SELECT BACK DOWN gt Buzzer Bicolor LED 9 1 Operation User interaction with the device is based on a hierarchical menu Menu items adjacent to a contiguous vertical line can be navigated to and from with the UP DOWN keys The SELECT and BACK keys work similarly on the horizontal direction Depending on the menu context the SELECT key can also select a certain action or item Most menu items are self explanatory Some require a few comments though SET IR CONTROL allows the user to capture and associate a particular IR command with any program that was already stored This feature makes it possible to use any IRRC IR remote control and with just the push of a button trigger the execution of any stored program as explained at the beginning of this paper Design note The IR receive and IR transmit diodes must be physically on the opposite sides of the box The Bicolor LED is meant to indicate remotely the mode The BrainlRac is in using a combination of blink rates and colors Page 13 of 14 The BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest A STANDBY OFF CAPTURE 20 PLAY PROGRAMS SET IR CONTROL SET TIME Y Figure 11 User Menu
12. his macro could be saved as XYZ TV macro and be run whenever a customer inquires about this TV set 4 Overview of IR remote control data transmission AIL IRRCs infrared remote controls share the basic concept of communicating to the home entertainment device using infrared light There is no standard when it comes to IR remote control for audio video equipment All major vendors use proprietary protocols Some quasi standards do exist These include RC 5 RC 6 SIRC Many manufacturers such as NEC have also established their own standards Atthe physical level data transmission is based on a few principles of modulation that have been established by most systems o Use of a carrier with frequency between 25kHz and 80kHz Carrier duty cycle can be anywhere from 1096 to 9096 The use of a carrier provides immunity from IR ambient noise Fluorescent lighting is one source of such noise Carrier transmission is accomplished by turning the IR emitter ON and OFF o Use of OOK ON OFF keying carrier modulation That is to say bursts of pulses at the carrier frequency are transmitted o Binary information is encoded by modulating the carrier using one of the following three techniques PWM pulse width modulation PDM pulse distance modulation or Manchester bi phase There are further variations of data formats with and without start stop burst with different numbers of bits in a command and with different bit leng
13. sign goal is the efficient use of storage memory A basic form of data compression needs to be implemented To that end the protocol header is defined as a list of four parameters that uniquely define that protocol These parameters are 1 Carrier Parameters Carrier parameters refers to the pair of values t1 t2 that represent the carrier on carrier off time Figure 8 Carrier parameters 2 Start Stop Information It shows whether the IR packet is preceded or succeeded by carrier bursts and it records their length 3 Encoding Method Specifies one of the three encoding methods PWM PDM Manchester 4 Packet to packet interval Specifies the amount of time separating one packet from the next one during a burst The strategy is to store the attributes for each protocol encountered only once and then reference them as needed via protocol headers Multiple headers are used to accommodate different protocols Another useful observation is that quite often a packet is repeated with a certain burst frequency for as long as the user keeps pressing the same key on the remote Therefore it makes sense to look for trains of identical packets and use run length encoding whenever they are detected These concepts are illustrated in Figure 9 Page 8 of 14 The BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest PACKET TO PACKET3 PACKET TO PACKET PACKET TO PACKET2 PACKET TO PACK
14. tandard IR receiver frontend devices Each device would be centered on a different carrier frequency such that together they would cover the whole range 6 9 Watch Timer This is a function that could be used However there are some drawbacks as will be shown later It works with 32 768 kHz subsystem clock to generate an interrupt request INTWTI at 0 5 second intervals thus maintaining an RTC real time clock The ISR interrupt service routine updates the RTC registers in RAM it also checks for a match between current time and any of the time alarms programmed to trigger execution of a particular program 7 Low Power Design Considerations When battery life is a concern as is the case here designing for lowest power is a major goal A decision regarding the RTC real time clock implementation can have a major impact on power consumption The obvious thing would be to use the internal Watch Timer However as the datasheet quickly reveals UPD78F935 flash still draws 12 in STOP mode with XT subsystem clock RUN In sharp contrast the uPD78935 mask ROM only draws 40uA in the same state The only way to bring uPD78F935 flash current draw at 10uA is to enter STOP mode with XT subsystem clock STOP Unfortunately turning off the XT clock disables the Watch Timer and with it the RTC This is the reason why this design shall use an external serial RTC featuring its own backup power and alarm interrupt output An added
15. ths Q Almost all codes have address bits and data bits Q Above the physical level the protocols differ in the way the address and data are encapsulated into the packet To illustrate three IR remote control protocols used by Sony Philips and JVC are presented This information comes from reference 2 4 1 Sony SIRC protocol carrier frequency Fc 40KHz carrier duty cycle or 1 3 bit encoding PWM a Logical Logical 4 gt 4 2 0 gt 4 50 00 gt Figure 1 SONY modulation Page 4 of 14 BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest 2Am 1 1 0 0 1 00 1 00 00 LSB MSB LSB MSB 51 Command 4 Address Figure 2 SONY packet 4 2 Philips RC 5 carrier frequency Fc 36KHz carrier duty cycle or 1 3 bit encoding Manchester ll 4 00 gt 4 90 14 900 4 900 Logic p Logic 1 Figure 3 PHILIPS RC 5 modulation Ame 1 1 0 0 1 00 1 00 00 LSB MSBiLSB MSB Start 4 Command X Address gt Figure 4 PHILIPS RC 5 packet 4 3 JVC carrier frequency Fc 38KHz carrier duty cycle or 1 3 bit encoding PDM Page 5 of 14 The BrainlRac Author Marcel Ursu Cornelius Van Drebble Mad Design Contest ioga 1 4 Logical 526 us gt e526 ys e 4 2 10ms _ gt 1 05ms
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