PJRC MP3 Player Pushbutton Circuit Board

Posted on Feb 4, 2014

This would be a lot easier with a display kit purchased from PJRC, which comes with the correct firmware installed on the display, a working pushbutton board, and the two cables needed. The PJRC display comes with a 4-pin plug that mates with the MP3 player, but it is easy to use with a PC instead of the MP3 player, as described above. But with a

PJRC MP3 Player Pushbutton Circuit Board
Click here to download the full size of the above Circuit.

raw display, the firmware chip that comes installed is useless and you must replace it with one that has the LCD. HEX firmware (that PJRC provides as a free download including source code, even though you purchased the LCD elsewhere!) You will need to program a flash rom or EPROM with LCD. HEX and replace the socketed chip that came with the board. You will need an EPROM programmer, and the correct DIP-PLCC socket adaptor to hold the chip while it is in the programmer (beware, the common 32-to-28 pin adaptor will not work, you need 32-to-32). The socket is wired for a 32 pin flash rom pinout, not the 28-pin 27Cxxx eproms that have 4 unconnected pins when purchased in 32 pin PLCC. I use the 39SF512 chip in the displays from PJRC. Update: now you can buy a pre-programmed firmware chip. PJRC provides these chips to allow you to make use of your JW-002 LCD (purchased from a third party), but PJRC does not provide the pushbutton board and custom ribbon cable separately for use with LCD purchased elsewhere. This step is absolutely required. If you don`t have an EPROM programmer, you must borrow or buy one, or find someone who has one to program the chips for you. No matter how badly you want those displays to work, you`re not going to get far with the original chip that comes installed with AT&T`s old firmware. The display does not care if you have access to an EPROM programmer or not. If you can`t get a chip with LCD. HEX...

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