Original documents from:
The EchoMp3 is a small DIY* MP3 player. It's cheap and of excellent quality.
* Do It Yourself.
Schematic & pcb (Eagle 4.11e), hex file available. Player Software Updated on February 8, 2008.
Circuit explanation / Getting started:
|PIC18LF45x PLCC||The 18LF452 or 18LF458 has to run at 20 MhZ due to the serial interface with the MMC. PLL cannot be used, cause it only works from 4V2. There's a quarter of ROM-space left for additional applications.|
|VS1002D:||MP3 decoder chip. Enhanced performance compared to the VS1001K. Sounds great! Future enhancements (equalizer and so on) are possible. Thanks to GBUF, no need for large capacitors at the earphone outputs. The chip also has a recording mode!|
|MMC/SD||Royalty-free and open source protocol makes this a great memory to work with. Finding a socket was more difficult. Format the card as FAT (FAT16) or FAT32, then copy them (all at once) to the card (with a cardreader.) Directories may be used. Tagging of your MP3 files can be done with Mp3 tag tools (freeware) and Audio Tags Editor (evaluation period.)|
|LCD||The LPH7779 (Nokia 3310 LCD) does the job. First four lines are for Artist and Song Title. Fifth line is for songnumber and elapsed time. Sixth line shows sample rate, bitrate and total songtime. Contrast of the LCD can adjusted during boot: hold the vol+ or vol- pressed at power up and the contrast will change accordingly; Settings are stored into the onboard EEPROM. Note that the player will also work without any LCD attached.|
|Controls||With the micro joystick, there are 8 user controls available. Two for volume (up & down) , track (left & right) , pause/play (short enter), skip (long enter) and directory scrolling (short enter, then up/down to scroll, enter to go to the selected directory.) Shuffle is enabled/disabled during boot (hold right at power up, then release.)|
|Power||On/off pushbutton. The MAX1674 DC-DC step-up converter makes it possible to power the whole circuit from only one AAA battery. Some larger SD cards will not boot with a weak battery though. A 1.5V alkaline battery performs better than a 1.2V NiMh.|
|PCB:||We used as much SMD-parts as possible. Number of vias reduced to 54, only the bottom pads of the PLCC-socket need to be soldered. The PCB from our shop is a double sided and 100% connection tested PCB with plated-through-hole connections. All holes are drilled already. PCB size = 82 x 45 mm or 3"29 x 1"77.|
Schematics: (eagle-file can be downloaded below.)
|VS1002D||PIC 18LF45x||MMC/SD||PIC 18LF45x||
|PIC 18LF45x||LCD-LPH7779||PIC 18LF45x|
|SDO||SDI, RC4, pin25||1 - XCS||RA1, pin4||Volume Up / contrast + / Directory scroll up||RE2, pin11||1 - VDD|
|SDI||SDO, RC5, pin26||2 - SDI||RA4, pin7||Volume Down / contrast -/ Directory scroll down||RE1, pin10||2 - SCLK||RD5, pin31|
|SCLK||SCK, RC3, pin20||3 - GND||Next Track / Shuffle||RE0, pin9||3 - SDA||RD4, pin30|
|XCS||RC2, pin19||4 - VDD||Previous Track||RA5, pin8||4 - D/C||RD1, pin22|
|XRESET||RB6, pin43||5 - SCK||RA2, pin5||Pause / Play / Fast Forward (FF)||RD6, pin32||5 - CS||RD3, pin24|
|6 - GND||6 - GND|
|DREQ||RB1, pin37||7 - SDO||RA3, pin6||7 - VOUT|
|BSYNC||RB4, pin41||8 - RES||RD2, pin23|
Downloads: right-click & "save as"
|WARNING: may not be duplicated for any commercial use whatsoever without explicit consent from the author (c) Michel Bavin, TechDesign Electronics.|
|PCB: 020v1420.brd (Eagle 4.11e) June 5, 2005.|
|PIC Hex files: (Re)Programming of the PIC can be done via the RS232 bootloader connector (see below) and Tiny PIC bootloader 1.8|
|Bootloader PIC Hex file: 18F452_hs20.HEX (only needed for development)|
|PIC Source Code: not released, but you can buy a license on this Products page.|
Info & datasheet:
|VS1002D mp3 decoder LQFP48|
|ID3 v2.3.0 informal standard.|
|The private life of MP3 frames.|
|Kingfont MMC socket SDCMF-10715W111|
|Graphic LCD module type LPH7779 (NOKIA 3310 LCD) and its integrated controller PCD8544.|
|MAX1674 DC-DC step-up converter|
Look here to build the (very simple) bootloader hardware.
Download the Tiny PIC bootloader from the same site. We are using version 1.8 (Don't use version 1.91)
PCB (real size = 82 x 45 mm or 3"29 x 1"77 )
The PIC code was made with the PCWH CCS compiler ($425,-); you can install Microchip's MPLAB IDE (click on the link and you can get it for free) with it to get things running smoothly.
Programming of the PIC was done with the excellent Tiny PIC bootloader, through the RC6 & RC7 pins. However you will need a regular PIC programmer to write the PIC the first time with...
Eagle 4.11e was used for the schematic & PCB layout.
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