Medianut - Ethernut
Contents
1. 26 XRESET Asynchronous PB7 o reset input 18 AGND Analog ground DC and GND via on board 3 3 Volt regulator AVDD Analog power Digital ground Digital power 15 Medianut User s Manual LCD Interface The 16 pin connector can be used to attach standard alphanumeric displays However most LCDs require a 14 16 pin single line connector while Medianut offers a 16 pin connector with 2 lines of 8 pins 14 pins are typically used for LCD control two additional lines are used for backlight supply In order to save Ethernut port pins Medianut drives the LCD in 4 bit mode and doesn t support reading LCD registers Instead one port bit has been spend to switch the backlight on or off Display backlights differ and you need to check your datasheet before enabling this feature Carefully check the schematics for correct polarity and either mount R13 and R14 most common or R12 and R15 reverse polarity While R14 and R15 are 0 Ohm and may be replaced by a simple wire the values of R12 and R13 require some calculation first to fit your display In most cases the LCD will not show any characters when used with Medianut for the first time You need to adjust the potentiometer R16 for optimum contrast In any case we recommend LCD compatible VFDs Allthough costly these are very bright displays with high contrast and do not require backlit supply or contrast adjustment Pin LCD Si2. 31 52 2 0 1 8X 21531 zi fag ees eee 19810 11531 WI 81531 s z w N 5 0 QWLX gt AI EE Tassusn 6 1155 Ro ONASSN 8 GI 2193042 SISA Z 5958 5 be 91905 DSSAESd 5 gt 5 3 91995155 G 2 0340 IDIA Np TOTTI 112551 E IL 13538 Doz _ 5 17 EGA She ONE 03905939 il alg os LE x OSSA oe _ 9121 S42 if 1 i g 086 cnp 8E TISH4S 4 9519 bla 33 18 Medianut User s Manual Z 9945 60 04 01 EBB 8 222 USIUT pue fitddns aN9 jupaw 095 aruba 1 1 Slut 8 0 1 4 9 512 Z EONNOY 09d LNNOW SX f
3. important statements are mp3buf NutSegBufWriteRequest amp rbytes Requests buffer space for writing rbytes will receive the number of bytes available and the function returns a pointer to the beginning of the buffer space got NutTcpReceive player psi sock mp3buf rbytes Calls the TCP IP receive routine to copy the application data into the buffer The function returns the number of bytes copied which may be less than the number of bytes requested NutSegBufWriteCommit got The number of bytes filled into the write buffer are commited and hence available for the driver The memory management routines are not interrupt or thread save and currently support one system wide buffer only But they are fast and simple to use Typical Nut OS drivers use a very simple interrupt routine which posts an event to a worker thread For performance reasons the MP3 decoder driver accesses the buffer directly within its interrupt routine Otherwise the decoder may run out of MP3 data due to the latency between posting an event and waking up the worker thread The application has to disable interrupts each time it calls a segmented memory management API While reading this chapter you may have asked yourself why it s called segmented memory The API can not only handle a continuos memory space but also one that is divided into several segments This is usefull with banked memory hardware provided by Ethernut 2 boards MP3 Decoder Driv
4. 2 NO 1 0 1 VS aNgy BENI cada 1za 619 7022 5 ON9Y gt 5 5 SAN Ss she ON9Y aany EI ganS 267 Leet ugat peat Lear 2 99 5 819 919 919 212 Jz N9 0000 7 515 Te 21 INO HoR T ene ino NI 2 5 Sani dWIBF6ENTI 991 IE lt O bX 3 3 g 19 Medianut User s Manual QS 18 i a Mmm XK OS gt 20 53 45 27 Omm nT 3 TE Pi So vel N A O i LO i N 00 55 9 20 21 Medianut User s Manual 21 egnite Software GmbH Phone 49 0 2323 925 375 Westring 303 44629 Herne Germany Fax 49 0 2323 925 374 Email info egnite de http www egnite de http www ethernut de
5. Medianut User s Manual Version 1 1 Copyright 2004 egnite Software GmbH All rights reserved egnite makes no warranty for the use of its products and assumes no responsibility for any errors which may appear in this document nor does it make a commitment to update the information contained herein egnite products are not intended for use in medical life saving or life sustaining applications egnite retains the right to make changes to these specifications at any time without notice All product names referenced herein are trademarks of their respective companies Ethernut is a registered trademark of egnite Software GmbH Contents 1 ABOUT THE MEDIANUT erre 5 IMEDIANUT lei i E A A a i ia i 5 2 nia aaa ea ein ariana 6 PREREQUISITES FOR OPERATION 0 Lee 6 BOARD INSTALLATION idea 7 3 NUTPIPER INTERNET RADIO APPLICATION 8 NETWORK CONFIGURATION 0 00 00000 8 RADIO STATION CONFIGURATION 0 000 9 USING THE REMOTE 9 SCANNING STATIONS IN THE BACKGROUND ccccescecceeecceeeeuuceeeeseueeecgateuveueeeeuatteeguuneeeuetensuags 10 4 CREATING YOUR OWN APPLICATIONS rr rire 11 NETWORK API i 11 SEGMENTED MEMORY MANAGEMENT cccsecceeccceeeeucceuevceeeeuueeeesauetecgutensaueereuaet
6. R socket near R10 on the Medianut The lense of the decoder must point to the board s edge 5 Attach the speakers or earphones to the Medianut audio output connecter 9 When using earphones never put them on while switching on or off your equipment Because of the risk of hearing damage we strictly recommend to use speakers 6 Optionally attach the LCD or LCD compatible display to the Medianut LCD connector 7 7 Attach the Medianut to the Ethernut expansion connector Make sure that smaller connector X2 of the Medianut board is placed near the Ethernut serial port and that both ends do exactly fit to the Ethernut expansion connector 8 Connect the power supply to the barrel connector on the Ethernut board You are now ready to upload your application code to the Ethernut or use the Nutpiper radio application sample See the next chapter for a detailed description of the Nutpiper program Medianut User s Manual 3 Nutpiper Internet Radio Application Sample Listening to the worl wide web The Nutpiper application turns your Ethernut Medianut system into an Internet Radio by using the Shoutcast protocol The application is still limited and experimental For example there is no other way to add new radio stations than to modify and recompile the code Only LCDs with 2 lines and 16 characters each had been tested and only Sony TV remote controls are currently supported So do not expect a full fledged radio but take it as a basis fo
7. a data most Shoutcast servers do the second line will display the stream title typically the interpret and the title of the track As you may know from other Ethernut applications or your webbrowser connecting a station which is not available may take upto a minute or more That s annoying but no solution is available yet Pressing power off will display the message Shutdown while the current configuration is stored in EEPROM When done the display will be cleared but no part of the system will be powered down More remote control features are available when enabling the background scanner Scanning Stations in the Background The code includes a highly experimental part called scanner which is disabled by default To enable it uncomment the line ScannerInit in the file nutpiper c This will start an additional thread which scans the list of stations in the background The user may press the Videotext button on the remote control and wlak through the list of stations using the channel plus minus buttons When pressing the input select button the radio will switch to the currently displayed station Pressing the Videotext button will return to the normal display 10 Medianut User s Manual 4 Creating Your Own Applications Make your wildest ideas come true As explained in the previous chapter the Nutpiper application is just an example for building your own Ethernet enabled MP3 devices Fortunately almost all
8. address the first slash the colon and the port number The above sample would consume 3 out of 19 bytes available After recompiling and before uploading the code to an ATmega128 board make sure that the fuse Preserve is off Otherwise Nutpiper will still load the old configuration from EEPROM and ignore ConfigResetFactory On the ATmega103 there is no such fuse and the EEPROM is cleared on each chip erase Storing the configuration into the EEPROM is done by pressing the power off button on your remote control Using the Remote Control Only Sony TV remote controls are currently recognized The supported code are defined in the driver dev irsony h The ten channel buttons 1 to 9 select the radio station entries 1 to 9 If Ethernut fails to connect the selected station the display will show the IP address and the message not available Channel selects plus and minus can be used to select the next or previous entry If the connection fails Nutpiper will automatically try the next or previous entry As soon as a station is connected Nutpiper will start buffering the stream and start the MP3 decoder as soon as the buffer is filled On Ethernut 2 this may take a while and you can force the decoder to start by pressing a volume button 9 Medianut User s Manual When Ethernut received a valid ICY header from the server it will display the name of the station in the first line of the LCD If the server provides met
9. dianut User s Manual This must be replaced by the IP address of the Internet gateway normally the IP address of your Internet router Radio Station Configuration In the current version there is no user interface for adding or removing radio stations The code comes with various predefined stations some of which offer terrible music To add your own stations edit the file config c When started for the first time or after a previously erased EEPROM Nutpiper will not find a valid configuration in the EEPROM and call the routine ConfigResetFactory which contains several calls similar to ConfigStation MAXNUM STATIONS 129 217 234 42 128 8000 Each call adds a radio station to the list and requires two parameters The first one is the index of the entry ranging from 0 to MAXNUM STATIONS Any index from 0 to MAXNUM STATIONS 1 will replace that entry If MAXNUM STATIONS is given the entry will be put the first unoccupied space The second parameter specifies the URL without leading http In the above example Nutpiper will connect IP address 129 217 234 42 on port 8000 and request 128 Btw it looks like this is a 128 kbit stream but in fact it s 56 kbit only Some time ago this station which is located at the University of Dortmund Germany and named elDOradio reduced the bitrate You can add upto 128 stations as long as the whole configuration fits into 3 5 kByte leaving 19 bytes for each URL parameter excluding the IP
10. e decoder e MPEG audio layer 1 2 and 3 ISO 11172 3 e MPEG 1 amp 2 for all layers and layer 3 s 2 5 extensions and all their sampling rates and bitrates in mono and stereo e Variable MP3 bitrates e Stereo earphone output capable of driving a 30 Ohm load e 40 kHz infrared remote control receiver easily replaceable by 36 or 38 kHz receivers e Standard 16 pin LCD interface with LED backlight control Medianut User s Manual 2 Quick Start This chapter will help you quickly set up and start using the Medianut board Prerequisites for Operation The following hardware items are necessary to run the Medianut board An Ethernut Starter Kit or an Ethernut Board plus programming adapter and a straight through serial communication cable with a DB 9 female on one end and a DB 9 male connector on the other Your Ethernut board should be equipped with an ATmega128 red colored board It is possible to run MP3 applications on ATmega103 equipped boards green color but the lower performance limits its use and not all function may work as expected Two straight through twisted pair cables together with 10 Base T hub or switch or a twisted pair cross cable if you don t got a hub or switch If you want to run the Nutpiper Internet Radio you need a local LAN with Internet access typically provided by a router with NAT support An unregulated power supply matching your local mains lt should supply DC 8 12V on a standard 2 1 mm barre
11. ection 1 Data output PE4 interrupt 4 input 2 Power supply GND DC and GND via on board 5 Volt 3 supply 5V regulator Power Supply Medianut takes its power supply from the regulated 5 Volts line of the Ethernut expansion connector and provides its own regulator IC6 to create the required 3 3 Volts for the MP3 decoder 14 Medianut User s Manual Expansion Port The board is equipped with two connector groups to be attached to the Ethernut expansion port Each connector group is located on one side of the board and divided into two connectors Address and data bus lines are not routed to the board to avoid interference with the sensitive analog audio part Connector group X1 X2 is used to attach the board in a compact way to the Ethernut However this makes a large part of the board inaccessible for measuring equipment in case of hardware problems With connector group X3 X4 the board can mounted in a 90 angle which makes it possible to easily access all parts on both boards This is very useful for tracing hardware problems By default X3 and X4 are not mounted Pin MP3 Decoder Signal Ethernut Connection ta request PE6 interrupt 6 input Data input clock 1 SCK output 3 SDATA Serial data PB2 MOST output input 4 BSYNC Byte PB5 output li Li 12 SCLK Control bus PBO output 13 SI Control bus input 14 5 1 bus output MISO input
12. ed from the decoder 13 Medianut User s Manual 5 Functional Hardware Description This chapter explains the hardware of the Medianut board Infrared Decoder Interface Use a tiny screw driver to attach the infrared decoder which comes with your board The lense should point down when plugging it into the terminal The decoder is working optimal with 40 kHz signals mostly used by Sony Decoders for 36 or 38 kHz are available upon request MP3 Decoder Generally the MP3 decoder is connected via two serial busses The first one the data bus is used to transfer the MP3 data stream from the Ethernut board to the decoder This bus will be driven by the Ethernut hardware SPI The second bus is used by the Ethernut board to read register contents from and write register values to the MP3 decoder Of course this is a bidirectional bus and has to be managed by software In order to save 1 0 lines both busses share the same data line from the Ethernut board to the MP3 decoder However the paranoid designer spent an additional port bit to control the decoder s hardware reset line Note that all port bits are routed via a 74LVC245 bus driver to convert the signal levels between the 5 Volt logic of the Ethernut board and the 3 Volt logic of the MP3 decoder IR Receiver The infrared receiver requires just a single port bit Falling and rising edges from the receiver output will generate interrupts Pin IR Receiver Signal Ethernut Conn
13. er This interrupt driven driver does all the low level handling of the VS1001K chip In order to use it an application must call VsPlayerlnit once during initialization and VsPlayerReset each time before playing a stream As soon as some MP3 data has been filled into the buffer see previous chapter the application will call VsPlayerKick to start the driver feeding the decoder From that point on the driver expects the application to keep the buffer filled If it runs out of data the driver will stop feeding the decoder and the application must call VsPlayerKick again as soon as more data is available again By calling VsGetStatus the application can query the status of the decoder It returns any of the following values 12 Medianut User s Manual VS STATUS STOPPED Player is ready to be started by VsPlayerKick 5 STATUS RUNNING Player is running VS STATUS EOF Player has reached the end of a stream after VsPlayerFlush has been called VS STATUS EMPTY Player runs out of data VsPlayerKick will restart it A call to VsPlayerFlush mentioned above will move all remaining MP3 data to the decoder and stop gracefully In the Nutpiper application this isn t used instead the decoder is reset when changing the radio station When playing single tracks from some external media or more important short samples from internal memory you should call it to make sure that all data left the audio output before resetting t
14. etguanereuntenagags 11 MP3 DECODER DRIVER ca iii 12 LCD INTERFACE rata 13 INFRARED REMOTE CONTROL 100 00 ceri 13 5 FUNCTIONAL HARDWARE DESCRIPTION rr rr 14 INFRARED DECODER 14 DECODER 14 ee ies are a ole ee ae ween ae 14 POWER SUPPLY ii aa 14 EXPANSION POR eoe meaa Alici 15 LED _ 16 KEYBOARD ira 17 AUDIO OUTPUT CONNECTOR oe n 17 SCANNER ii 17 6 SCHEMATICS AND BOARD LAYOUT 18 Medianut User s Manual 1 About the Medianut Board MP3 for Embedded Ethernet Applications Medianut is a small 40 x 98 mm add on for the Ethernut board combining VLSl s VS1001K decoder with Ethernut s embedded Ethernet which is well suited for developing a wide range of applications Some areas are e Internet radios also known as WebRadios e Talking Ethernet devices e Ethernet enabled MP3 players Medianut Features The Medianut board provides the following features e VS1001K hardwar
15. gnal Ethernut Connection 1 Power supply GND DC and GND via LCD on board regulator 2 Power suppl 4 L Instruction PE2 output register H Data register Read Write control None tied to GND to LCD LCD trobe output tied to GND in 4 bit mode Alm vi 5 t H 5 da try Be gt 5 5 5 ct H 5 f H i Pi 5 5 O ct 5 5 ct Q t suppl GND via on board 5 Volt and power MOSFET controlled light supply tput Ea ea ES Es 12 Data ln E 16 0 16 Medianut User s Manual Keyboard Interface The keyboard is currently not supported by the software but may be useful for your own application Four switches may be attached each of which will connect one of the four lower port bits of port D to ground when pressed Audio Output Connector The stereo output may be connected to an earphone an amplifier line input or active speakers It is capable of driving a 30 Ohm load Please be carefull when using earphones always remove them from your ears before attaching or detaching connectors playing around with untested software or switching on and off the power supply Even with the tiny amplifier of the Medianut you can
16. he decoder Some additional routines are provided for volume control zero of maximum volume querying MP3 information AVRGCC only setting special decoder modes see VS1001K datasheet or testing the internal decoder memory LCD Interface The LCD driver currently supports HD44780 compatible display controllers only but the majority of alphanumeric displays follow this standard On the other hand the display support provided by Nut OS is very comfortable when compared to other LCD implementations Except for initialization no special calls are required the driver is fully integrated into stdio library and features a superset of VT52 emulation for cursor and write position control This makes it for example very easy to switch from RS232 terminal output to LCD output and vice versa See the Nutpiper application for how to use the LCD Infrared Remote Control A first attempt to provide a unified IR driver interface had been made for the Sony protocol In general decoding IR commands is a very time sensitive task which easily conflicts with other realtime demands like MP3 streaming or Ethernet I O The Nutpiper application proofs that all task could be done on one ATmega128 CPU concurrently Ethernuts running on ATmega103 may face problems though The corresponding API interface is very simple Beside standard Nut OS device registration which initalizes the driver NutlrGet is the only routine and will return the raw code receiv
17. l connector The total power consumption depends on the display used but 500 mA should do in most cases A standard PC equipped with Linux or Windows 98 NT 2000 XP an available serial COM port and a twisted pair Ethernet adapter card An AVR development environment either AVR GCC for Linux or WinAVR or ICCAVR for Windows An active speaker set or a stereo headphone with 30 Ohm minimum impedance A high end amplifier with some bulky JBL speakers will do as well A standard LCD or LCD compatible display and a Sony TV remote control would be more fun and are required to run the Netpiper application sample An adapter may be required to connect the LCD You may also need a tiny soldering iron to mount two SMD resistors in order to enable LED backlight control A 4 bit port to optionally attach a simple keyboard Medianut User s Manual Board Installation 1 Remove the board from the antistatic bag Visually inspect the board to verify that it was not damaged during shipment N WARNING As with all computer equipment the Medianut board may be severely damaged by electrostatic discharge ESD Be sure to take proper precautions before removing the Ethernut board from the anti static bag 2 Setup the Ethernut as explained in your Ethernut hardware manual Do not switch on the power supply before attaching the Medianut board 3 Attach you programming adapter to the Ethernut board 4 Plug the infrared decoder to the I
18. lity this will fail because TCP isn t realtime but playing MP3 is So at least one buffer stage is required to compensate the non deterministic arrival of TCP data Each packet received is moved from the Ethernet controller into a so called NETBUF Each NETBUF is added to a connection specific queue until the application request data from the connection For portability reasons and to keep things simple the application provides a buffer and calls NutTcpReceive to get that buffer filled with application data out of the queued NETBUFs This is another copy but frees the application from dealing with system specific NETBUF structures The smart part is that Nut OS offers a special buffer management to avoid the final copy into the decoder buffer and that the Nut OS MP3 decoder driver makes use of this buffer management As stated normally the application buffer is filled by some kind of read statement first copy and transfered to the driver 11 Medianut User s Manual by some kind of write statement second copy When using the segmented memory management the application will query the driver for buffer space first and then pass this buffer to the TCP read routine This way the TCP read routine will directly fill the buffer of the decoder driver When this has been done the application commits the buffer filled and requests a new one and so on This technique is used in the Nutpiper application file player c inside THREAD Player The
19. low level functions are provided by Ethernut s operating system Nut OS This chapter contains some basic introduction more details are available in the Nut OS API documentation Network API Ethernut s TCP IP stack named Nut Net provides the required socket API Check the Ethernut manuals and samples to become familiar with it While Nut OS can map socket I O to standard I O functions like and fscanf or write and fprintf these functions are not very usefull for MP3 streaming because of their additional overhead It is recommended to use the native Nut Net TCP Socket API instead like NutTcpReceive These functions are similar to the BSD socket library Segmented Memory Management decoding by software requires at least a 32 bit CPU with more than 100 Mips But even with a hardware decoder like the one used on the Medianut Board moving all the data in realtime from a TCP IP network to the decoder requires some special techniques to make it work on a tiny 8 bit system The key to success is avoidance of data copying Usually data streams are moved from the Ethernet Controller to the Ethernet s driver buffer then moved to the TCP buffer again moved to the application buffer and finally from the application buffer to the MP3 decoder buffer Some systems may use additional steps Nut OS tries to avoid these copies In extreme the data may be moved directly from the Ethernet controller to the MP3 controller In rea
20. r your own creativity When running on Ethernut 1 3 listening to Internet bitstreams above 56 kBit may not be possible With 32 kByte memory only a fraction of a second is available for buffering the stream The new Ethernut 2 0 is equipped with 512 kByte RAM and can even take 320 kBit streams if the server delivers the MP3 data at a sufficient rate Note that Nutpiper requires Internet access your local network must support this Network Configuration If your local network supports DHCP no code modifications are required to give it a first try Nutpiper will query its IP address network mask and default gateway from the DHCP server If DHCP is not available you need to edit the file nutpiper c Unique MAC address of the Ethernut Board char mac 6 0x00 0x06 0x98 0x00 0x00 0x00 Change this to the unique MAC address of your Ethernut board Unique IP address of the Ethernut Board Ignored if DHCP is used ip addr inet 192 168 192 100 This must be replaced by a unique IP address within your local network Make sure that this address is able to access the Internet IP network mask of the Ethernut Board Ignored if DHCP is used u_long ip mask inet _ addr 255 255 255 0 Replace with the IP mask used in your local network Gateway IP address for the Ethernut Board Ignored if DHCP is used u_long ip gate inet _ addr 192 168 192 3 8 Me
21. severly damage your hearing Tiny earplugs are more dangerous than larger headphones Professionals prefer to use speakers while developing audio hardware and software Scanner Interface This interface is used with egnite s record shop system If you are an owner of a music shop chain you may be attracted Call us or send us an email for more interesting information Otherwise simply ignore it it s not there 17 Medianut User s Manual 6 Schematics and Board Layout 9 g 2 1 9 5 GZ Or CI 87 4 4 4 4 4 4 4 9De 49 UI pue TIUPSUW ONS 5 1 1 W OIRAN AT 8X o lololo 659814 IIE RI RR 5 lt jo 8X NIA 7 2 m lt m dee dee SRR 2 AT A gt 81 29 19 4 2105
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