[sdiy] Microchip DSP kit $60 > AVR32

Eric Brombaugh ebrombaugh at earthlink.net
Fri Mar 21 19:53:35 CET 2008


Scott Gravenhorst wrote:

>>> It has 4 stereo ins and four stereo
>>> outs, and optical digital in/out if you want it.
>> Is that last one for MIDI?
> 
> Ack!  How could I miss that?
> 
> Thanks Mr. Tellason, I hereby "un-poo".  
> 
> A digital in would do nicely, especially if the board has something that does the UART
> thing in hardware or if the MPU/CPU/MCU has a built in general purpose UART.  I don't like
> to use a processor to do the serial bit shift thing, I prefer a real UART so that the
> CPU/MPU/MCU isn't burdened with that.

As mentioned earlier, the optical capabilities of the Soundbite board 
don't include MIDI. The DSP56371 processor on the Soundbite doesn't have 
a UART either, so you'd either have to use an external processor to 
handle the MIDI interface and send the results in via SPI, or you'd need 
to bit-bang the UART function (Ugh!).

Available peripherals on the processor are:

— 2x Enhanced Serial Audio Interface (ESAI): up to 4 receivers and up to 
6 transmitters (per each), master or slave. I2S, Left justified, Right 
justified, Sony, AC97, network and other programmable protocols.
— Serial Host Interface (SHI): SPI and I2C protocols, multi master 
capability in I2C mode, 10-word receive FIFO, support for 8, 16 and 
24-bit words.
— Triple Timer module (TEC).
— 11 dedicated GPIO pins
— Digital Audio Transmitter (DAX): 1 serial transmitter capable of 
supporting the SPDIF, IEC958, CP-340 and AES/EBU digital audio formats.
— Pins of unused peripherals (except SHI) may be programmed as GPIO lines.

The low GPIO count and Serial Host Interface should be a clue that the 
intended purpose for this part was as a simple stand-along DSP, or as a 
peripheral to another processor which sends it commands via the SHI. If 
I were doing MIDI with this, that's where I'd start.

Eric



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