[sdiy] STM32 (or other) audio DSP learning recommendations

[Scott Gravenhorst]

Eric Brombaugh <ebrombaugh1 at cox.net> wrote:
>On 07/06/2018 07:34 AM, Scott Gravenhorst wrote:
>> 
>> One of the odd things about the WM8731 is the "SPI compatible" 
>control port. I would have > expected I2c, but that is not the 
>case. 
>
>The WM8731 can work in either I2C or SPI modes, depending on the state 
>of the MODE pin (21). When it's held at logic 0 the device uses I2C 
>protocol and when it's pulled up to logic 1 then it operates in SPI 
>mode. I used I2C mode in my STM32F4 Codec board and it works fine.
>
>One thing to be very careful of is that Wolfson in their wisdom located 
>the serial clock pin and the main oscillator input pin right next to 
>each other. This makes the serial clock extremely susceptible to 
>interference from the main oscillator when building prototypes on 
>solderless breadboads or with flying hookup wire. If you find you can't 
>talk to the device double check that the serial clock line is not being 
>contaminated.
>
>Eric

Thanks Eric, that is good to know.  I probably glanced over the I2C stuff in the
datasheet.  The two examples I've seen both used the SPI mode, but good to know that
I2C can work too.  Can I assume that regardless of I2C or SPI, the CSB line still
needs to be set low and set high to latch the data?  I was unaware of the clocking
issues and as it turns out, I'll be working with a fly-wire prototype.  Perhaps
shield would be a better way to connect it to my Nucleo.

-- ScottG
________________________________________________________________________
-- Scott Gravenhorst
-- http://scott.joviansynth.com/
-- When the going gets tough, the tough use the command line.
-- Matt 21:22