[sdiy] ARM based digital synth.

[Eric Brombaugh]

On Sep 13, 2006, at 7:53 PM, Alwyn Lloyd wrote:
>
>
> On Wed, 13 Sep 2006, Eric Brombaugh wrote:
>
>>> What i have found out though is the phillips chip have 2 SPI ports, 
>>> and
>>> can be run at a maximum of 1/8th of the clock rate.  which is fast.  
>>> I'm going
>>> to have a look at whether i2s and spi are close enough that one 
>>> could use
>>> the spi ports as i2s ports.
>>
>> Interesting idea. There was an article in the latest issue of Circuit
>> Cellar that described an I2S port implemented on a TI DSP using a SPI
>> port and some of the internal timers. You might be able to lash up
>> something like that - sort of half software & half hardware.
>
> Ooh, that sounds right on the money.  Do you have the issue number its 
> in?
> Magazines like that arive a bit later over here in AU.
>

OK - I checked in the magazine and I've got good news: It wasn't a TI 
processor - it was a Philips LPC2148 ARM processor. Not the same one 
used on the Futurlec board, but similar. He used one of the SPI ports 
(the SPII/SSP one) to send 16-bit data words to a CS4330 I2S DAC, plus 
an external inverter on the SCLK line and Timer1 to generate the Frame 
Select line.

The issue is #194 Sept 2006, page 40. "Digital Audio Player" by Jan 
Szymanski.

Eric