yampp - yampp-4

yampp-4

This is a DEAD project.
Please do NOT email me with requests for code or schematics for yampp-4. All mails even mentioning yampp-4 will be deleted. !!!!!

This is what I'm working with now. yampp-4 is an ATmega103 based player. This means 128 kB of program memory, as opposed to the 8 kB in the At90S8515. That means that besides a decent userinterface, there will be room for the USB code for driving the Phillips PDIUSB12 chip.

The decoding is still done by a MAS/DAC board, but I'm aiming for using the VS1001 when the new chip is released.

I'm currently using a small prototype board from OptiCompo. This is a very nice little board with a mega103, xtal, multiplexer, reset controller and ISP interface. It also has a 0,1" pinout so it's easy to use in a development board.

As can be seen from the pictures below, there is room for a '573 latch and an SRAM under the mega103 board.
However, it's not necessary to add this RAM. My current code version plays at least 256 kbps MP3 files just using the internal SRAM of the mega103. And I'm just running the mega103 at 3.68 MHz, so there's plenty of capacity left.
But for user-interface purposes and when I add the USB chip, some more RAM may be needed.

Update
Well, I've now added USB, and still it may be possible to do away with the RAM.
But it's so much easier with it. Larger buffers, and I don't have to play with overlapping variables to get it all in there.

I've been testing a new display for the yampp-4, a 128*64 graphic display.
While it looks great, it unfortunately put quite a load on the CPU. I get some problems when trying to play 256 kbps songs.
Anyhow, I've added some photos below of the yampp-4 with the new display.

I've also added a rotary switch. This makes a lot of selections, such as song and volume, much easier.

The USB links is also running pretty nice. The transfer speed is about 128 kByte/second. Not that amazing, but better than a serial link.
Also, it's easy to handle.
Just plug the yampp into an USB port, and it will show up as a normal diskdrive in "My Computer". You can then easily copy, move or delete files by drag & drop, just like any other disk.