[sdiy] Audio codec question

Richie Burnett rburnett at richieburnett.co.uk
Sat May 16 22:07:17 CEST 2015

As Paul said there are cheap microcontrollers with an I2S interface. 
There's also Microchip's range of DSPIC chips which are a kind of low-end 
DSP/microcontroller hybrid.  All of which are in the single dollar price 
bracket at volume.  Some of the DSPIC chips also offer a 16-bit stereo audio 
DAC built-in, which has fairly decent performance if you pay careful 
attention to PCB layout.  This takes away the need to set up the I2S 
interface and route tracks to an external CODEC chip if all you require is 
16-bit stereo audio out.  If you need audio in as well, or need to go up to 
24-bit then an external codec over I2S is the way to go though.

I'd recommend you take a look at Eric Brombaugh's dsPIC boards for examples 
of the CODEC interface, and built-in audio DAC on the dsPIC platform,

What are you trying to do?

At the end of the day I2S isn't really anything special.  It's just a serial 
interface like SPI, that runs with a continuous bit-clock and has an 
additional word-clock designating left and right channels.  You might be 
able to mimic it with an SPI port operating under DMA control and a few GPIO 
lines.  Just watch out for slight variations in communications standards 
like left-justified, right-justified, and an option that clocks the first 
bit of audio out one bit-clock late whose name escapes me at the moment.


-----Original Message----- 
From: Paul Schreiber
Sent: Saturday, May 16, 2015 8:35 PM
To: 'Tim Ressel' ; 'Synth-Diy'
Subject: Re: [sdiy] Audio codec question

STM32F3xx parts are a staggering $3 and have I2S. Look at the 'Discovery'
boards, they are like $9-$14 and have the CODEC and the part on a board.

Paul S.

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Tim Ressel
Sent: Saturday, May 16, 2015 12:30 PM
To: Synth-Diy
Subject: [sdiy] Audio codec question


Does anyone know of an audio codec that uses SPI instead of I2S?  It seems
the only processors that have I2S are rather high-end and I don't need that
much power.


Tim Ressel
Circuit Abbey
timr at circuitabbey.com
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