MP3 is Working, Maybe

Last time I described my basic plan of attack to solve this problem with the MP3.  There has been some progress.

The VS1053/1063 allows for a sweeping frequency tone output, which I didnt think was working.  After putting a scope on it, I saw that it was.  The frequency starts very low and slowly increases.  It was taking almost 60 seconds to get to an audible range. (After 20+ years in Naval Aviation, my audible range is not what it used to be.)  After seeing this on the scope, I finally heard it.  So the VS1053 is working.

I still could not get the MP3 file to play.  So I moved the Click board to an HPC Curiosity board where I had direct control of the SPI on a PIC18F47K40.  After fighting a K40 errata error I forgot about, I finally was able to play a very short MP3 file, 1695 bytes.  The MP3 file was embedded in the code.

I then moved back to the PIC32MX470 with the embedded MP3 file.  Still no sound.  Now I started putting printf statements everywhere to watch the buffer action.  I had double buffered the file.  The VS1053 will accept at least 32 bytes if DREQ is high. Thus I use a small buffer (we will call Buffer32) to transfer the file .  Thus I always transfer 32 bytes to the VS1053.  But to cut down on overhead, I read from the file in 512 byte chunks, except the first time where it is 1024 bytes, into another buffer (we will call Buffer1024).  The idea is to read 512 bytes in to Buffer1024 every time the pointer crosses 512 or 1024.  Then the play function reads out of Buffer1024 into Buffer32 and sends this to the VS1053. 

Well the buffer pointers weren't even close to doing what I wanted.  Just really dumb errors.  After cleaning that up, I am now listening to Tube Snake Boogie by ZZ Top.  The quality is not great, probably some problem with the data flow is not fast enough yet.  But at least the basics are working.

The driver needs a lot of cleaning up and it may be awhile before I get there.I am committed to publishing this driver so either watch here or the Microchip forums for more info.