Pattern Generator to Generate I2S

[Logan B]

After reading the documentation its not entirely clear what I can get out of the pattern generator.
 

I'd like to send custom messages via I2S and other protocols with the click of a button. For example, enter the data I want to send, and the device sends the specified data via the specified protocol automatically. Is this possible with the pattern generator on the Digital discovery device or any other devices?

 

Also I see the analog discovery 3 does not list I2S as a supported bus protocol. This seems odd as it is the more premium product than the digital discovery. Is this correct?

Edited February 22 by Logan B

[attila]

Hi @Logan B

For I2S output custom signal can be used from Pattern Generator. Decoding is supported in Logic Analyzer.

[plswelcomeroh]

Hi Attila,

 

Even though I set I2S pattern in Logic of W/F, I could not make any pattern output.

So could you please share the project file for I2S pattern 1KHz sinewave @48KHz sample?

 

Thanks in advance.

[attila]

Hi @plswelcomeroh

See the following:

For more samples use configuration with deeper Pattern device buffer. I2S rate will be frequency / 2 / bits_per_channel

const cbit = Patterns.Channels.DIO2.Samples.value;
const bps = 16;
const csample = cbit/bps/2;
var rgsel = [], rgdat = [];
print('bits:',cbit,' samples:',csample);
for(var j = 0; j < csample; j++){
    var v1 = round((1.0+sin(2.0*PI*j/csample))/2*(pow(2,16)-1));
    for(var i = bps-1; i >= 0; i--) rgdat.push((v1>>i)&1); // left
    for(var i = bps-1; i >= 0; i--) rgdat.push((v1>>i)&1); // right
    for(var i = 0; i < 2*bps; i++) rgsel.push(((i+1)%(2*bps))<bps?1:0);
}
Patterns.Channels.DIO2.custom = rgdat;
Patterns.Channels.DIO0.custom = rgsel;

 

[plswelcomeroh]

Hi Attila,

Thank you for supporting it.

 

Is there any limitation on the PLL divider? what I mean is how do I set 12.288MHz for I2S?

And could you please share your project file?

 

Thanks!

[attila]

Hi @plswelcomeroh

i2s.dwf3work

With Digital Discovery and ADP3X50 you can generate wide range of frequencies, and with AD3 and ADP2230 the frequency option resolution is lower, closest to 12.288M is 12.305MHz but 0.14% difference is probably acceptable.