Adafruit_ZeroI2S I2SMCK0 Grand Central M4 Express

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3pb
 
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Joined: Sat Aug 13, 2022 9:11 pm

Adafruit_ZeroI2S I2SMCK0 Grand Central M4 Express

Post by 3pb »

Greetings.
Using the Adafruit_ZeroI2S library with the Grand Central M4 Express.
Testing the example programs basic.ino and tone_generator.ino.
Pins 32 and 33 show data output and word clock, as documented on page https://learn.adafruit.com/adafruit-gra ... al/pinouts, verified on the oscilloscope.

Browsing the library source, definitions for I2SMCK0 and I2SSCK0 also match the documented mapping to pins 15 and 14.

However, I can't generate a signal on pins 14 and 15, or a master clock signal on any other pin, for that matter.

I added a few lines to basic .ino, to verify the definition of pin of the audio clock

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Serial.print(F("PIN_I2S_MCK ")); Serial.println(PIN_I2S_MCK);
and to enable the master audio clock

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Serial.println(F("hello "));
  i2s.enableMCLK();
   Serial.println(F("hello again"));
I would appreciate advice on how to enable these signals.
Thank you.

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3pb
 
Posts: 10
Joined: Sat Aug 13, 2022 9:11 pm

Re: Adafruit_ZeroI2S I2SMCK0 Grand Central M4 Express

Post by 3pb »

After a little more studying, I tried to instantiate the i2s object using

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 Adafruit_ZeroI2S i2s = Adafruit_ZeroI2S(32, 15, 33, 31);
based upon definitions in
https://cdn-learn.adafruit.com/assets/a ... 1663982143

and still failed to generate the clock signal.

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3pb
 
Posts: 10
Joined: Sat Aug 13, 2022 9:11 pm

Re: Adafruit_ZeroI2S I2SMCK0 Grand Central M4 Express

Post by 3pb »

Actually, to get I2S going, I've been searching for the means to activate

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@param SCK_PIN bit clock pin
, which is defined for the Grand Central M4 to be pin 14 in file
C:\Users\*****\AppData\Local\Arduino15\packages\adafruit\hardware\samd\1.7.10\variants\grand_central_m4\variant.h

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#
define PIN_SERIAL4_TX      (14)
#define PIN_I2S_SCK         PIN_SERIAL4_TX
Still, neither

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Adafruit_ZeroI2S i2s = Adafruit_ZeroI2S();
nor

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Adafruit_ZeroI2S i2s = Adafruit_ZeroI2S(32, 14, 33, 31);
generate a clock signal

Not sure how to proceed, or interrogate registers to probe the status this clock signal.

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