Make Something Else
Home
 

Overview

News
MiniMintyMP3 Newsies history
last edited: May 31, 2005

May 30, 2005  

hello world!

set mode to 0x800
set clockf to 0x9800
starting tone test
set mode to 0x800
set clockf to 0x9800
MMC inserted!
Initializing MMC...
Initializing FAT16...
Fetching MBR..
Found FS 0x4: FAT16 signature 0xAA55 ok

Getting BPB from sector 0x33
bytes/sectors: 512
# sectors/cluster: 1
# reserved sectors: 1
# FATs: 2
/ entries: 512
FAT starts at sector 0x34
/ starts at sector 0x204

INFO 15 (cluster 0x2, sector 0x224)
TRACKS 578 (cluster 0x674F, sector 0x6971)
T02 MP3 4541544 (cluster 0x4, sector 0x226)
T01 MP3 4259840 (cluster 0x22AB, sector 0x24CD)
T03 MP3 4736731 (cluster 0x432B, sector 0x454D)
<EOD>
found
found INFO
found TRACKS
found T02 MP3
found mp3!
found T01 MP3
found mp3!
found T03 MP3
found mp3!

Umm, you'll have to trust me that music is playing. Looks good so far. Onto USB!

Also, I revived the large mmc flash card (a full reformat using a card reader did the trick)

 
May 10, 2005  

Fizzled my 256M mmc flash card. :(

Managed to squeeze a few different MMC FAT implementations together successfully. Unfortunately, this mcu doesnt have enough SRAM to buffer a whole sector so things are a little icky. Still, some sucess in reading the boot sector as copied from older code, which means I can pretty much just reuse the MintyMP3 fat16 code here.

Now I have to go buy another MMC card. I was always wondering if it were possible to just buy 16M ones. Turns out the only place I've ever seen them sold at so far is CVS, & for only ~$12!

  
May 8, 2005  

Grr. Was writing code on an ATmega8, then realized that it was being flakey because ATmega8's are 5V only and I need ATmega8L. Then decided I should just go with ATmega168. Ordered samples, then seems that said chip is not supported by AVRgcc so I ordered some ATmega88. Woo, those seem to work just fine.

Today I started speaking to the SD/MMC card successfully, although not reading any file system stuff. The free (procyon) code wasn't functional really. It needs a little bit of work to clean it up but I've already started getting it into shape.

Picture shows test board as it was before i swapped the chip: microcontroller, 2 x AAA, DC/DC converter, MMC card holder, and headphone jack with switch (turns player on and off)

  
April 18, 2005  

Woo! Some parts came in. More soldering tomorrow....

Note: MMC cards require a ridiculous 40-80mA. Thats a lot more than I expected...may have to upgrade the power supply.

Preliminary cost calculations seem to imply I can sell kits for less than $75.

  
April 17, 2005  

I finally get off my butt & make a webpage.

Progress currently is:

  • Overall functionality chosen
  • Virtually all hardware/chips have been specified and samples ordered
  • Created a topologically equivalent 'breakout' board for writing & testing firmware.

Current plan is:

  • Get microcontroller talking to SD/MMC card and parsing FAT16 formatting (should be easy, theres GPL code out there for doing it)
  • Get microcontroller talking to MP3 chip. (In particular, verify the GPIO pins). Maybe even get some muzik playing.
  • Get joystick to control volume & playback
  • Verify powersupply is sufficient.
  • Design battery charging circuit
  • Tackle USB mass storage code.
  • Keep tackling it
  • Hooray! Thats beta!

Mostly waiting for parts to come in & reading up on mass storage class.