Teensy 4.1 + MAX98089

[Myreauks]

Hi!

I am trying to interface the MAX98089 audio codec with Teensy 4.1. Mainly I am interested in this codec, as it has integrated speaker amp and some more interfacing options compared to SGTL5000.
I have a custom board based on the evaluation board reference design of the MAX98089. I have managed to establish I2C connection between the Teensy and the audio codec. I can successfully read and write registers with the Wire library. Even the jack detection works correctly.
However, I am having trouble getting the i2S connection to work. When reading the status register from the audio codec it says: "Either digital audio interface is configured incorrectly or receiving invalid clocks."

This leads me to believe that I have not managed to configure the codec correctly so that it would interface with the Teensy as the master.
The connections should be correct MCLK, BCLK, LRCLK, DIN and DOUT.

I have found this project, which also interfaces Teensy with MAX98089, but here the Teensy is a slave, so it is not much of help for my issue.
https://gitlab.com/amesser-group/ele.../-/tree/master

On page 85 of the datasheet of the MAX98089 it describes the process of setting up the clock source etc:
https://datasheets.maximintegrated.c...s/MAX98089.pdf

Here are some of my settings related to the audio input:
0x10 (MCLK prescaler) -> 01 (as Teensy MCLK is 11.29MHz)
0x11 (Sample rate) -> 0x7(44.1KHz)
0x12 I have tried to enable PLL mode, but not exactly sure about the settings on this one.

Here is the full code where I setup all the registers: (For now, I am just trying to get output on headphones.)

#include <Audio.h>
#include <Wire.h>
#include <SD.h>
#include <SPI.h>
#include <SerialFlash.h>

// GUItool: begin automatically generated code
AudioSynthWaveformSine   sine1;          //xy=411,453
AudioOutputI2S           i2s1;           //xy=596,455
AudioConnection          patchCord1(sine1, 0, i2s1, 0);
AudioConnection          patchCord2(sine1, 0, i2s1, 1);
// GUItool: end automatically generated code

int chordnum=0;

void setup() {
  Serial.begin(9600);
  AudioMemory(15);
  
  sine1.amplitude(1.0);
  sine1.frequency(400);

  Wire.begin();
  delay(700);

  beginMAX98089();
}

void loop() {
//  Serial.print("Max CPU Usage = ");
//  Serial.print(AudioProcessorUsageMax(), 1);
//  Serial.println("%");
//  maxRead(0x00);
  delay(1000);
}

void beginMAX98089() {

  // Check that MAX98089 is connected by checking the revision number, should always be 0x40
  Wire.beginTransmission(0x10);
  Wire.write(0xFF);
  Wire.endTransmission(false);

  int n = Wire.requestFrom( 0x10, byte(1));
  if( n != 1) {
    Serial.println( "requestFrom failed");
  }
  else {
  while(Wire.available()) { // slave may send less than requested
      byte c = Wire.read();   // receive a byte as character
      Serial.print("0x");
      Serial.print(c, HEX);        // print the character
      Serial.print(" ");        // print the character
    }
  }
  
  Serial.println();

  Wire.endTransmission();

  /* Proper Startup sequence
   *  
  1   Ensure SHDN = 0                       0x51
  2   Configure Clocks                      0x10 to 0x13, 0x19 to 0x1B
  3   Configure digital audio interface     0x14 to 0x17, 0x1C to 0x1F
  4   Configure digital signal processing   0x18, 0x20, 0x3F to 0x46
  5   Load coefficients                     0x52 to 0xC9
  6   Configure mixers                      0x22 to 0x2D
  7   Configure gain and volume controls    0x2E to 0x3E
  8   Configure miscellaneous functions     0x47 to 0x4B
  9   Enable desired functions              0x4C, 0x50
  10  Set SHDN = 1                          0x51
  
  */

  // Ensure SHDN = 0
  if(maxWrite(0x51, 0x00)) { Serial.println("Device disabled"); };

  // Configure clocks
  if(maxWrite(0x10, 0x10)) { Serial.println("MCLK Prescaler set"); };
  if(maxWrite(0x11, 0x70)) { Serial.println("Sample rate set to 44.1 KHz"); };
  if(maxWrite(0x12, 0x80)) { Serial.println("Clock mode set"); };
  if(maxWrite(0x1A, 0x80)) { Serial.println("Clock mode set"); };
  if(maxWrite(0x13, 0x00)) { Serial.println("Clock mode set"); };
  if(maxWrite(0x1B, 0x00)) { Serial.println("Clock mode set"); };

  // Configure digital audio interface
  if(maxWrite(0x14, 0x10)) { Serial.println("DA1 Format set to I2S"); };
  if(maxWrite(0x15, 0x00)) { Serial.println("DA1 clock just in case"); };
  if(maxWrite(0x16, 0x41)) { Serial.println("S1 routed to DA1"); };
  if(maxWrite(0x17, 0x00)) { Serial.println("DA1 TDM Slots"); };
  if(maxWrite(0x1C, 0x10)) { Serial.println("DA2 Format set to I2S"); };
  
  // Configure digital signal processing
  if(maxWrite(0x18, 0x80)) { Serial.println("Set music mode"); };

  // Configure mixers
  if(maxWrite(0x22, 0x84)) { Serial.println("Routed DA1 to Headphones"); };
  if(maxWrite(0x27, 0x00)) { Serial.println("Bypass headphone mixer"); };

  //Configure gain and volume controls
  if(maxWrite(0x2F, 0x00)) { Serial.println("Config DA1 Vol"); };
  if(maxWrite(0x30, 0x00)) { Serial.println("Config DA1 EQ"); };
  if(maxWrite(0x39, 0x1A)) { Serial.println("Set headphone left output & volume"); };
  if(maxWrite(0x3A, 0x1A)) { Serial.println("Set headphone right output & volume"); };

  // Configure miscellaneous functions
  if(maxWrite(0x49, 0x00)) { Serial.println("DAI 1 EQ config"); };
  if(maxWrite(0x4B, 0x80)) { Serial.println("Jack detection enabled"); };

  // Enable desired functions
  if(maxWrite(0x4D, 0xC3)) { Serial.println("Enabled headphone & DAC output"); };
  if(maxWrite(0x4E, 0xF0)) { Serial.println("Top level bias set"); };
  if(maxWrite(0x50, 0x0F)) { Serial.println("Enabled DAI clock gen"); };

  
  
  
  // Set SHDN = 1
  if(maxWrite(0x51, 0xC0)) { Serial.println("Device enabled"); };
  
  delay(1500);
  maxRead(0x00);
  
}

bool maxWrite(unsigned int reg, unsigned int val) {
//  if (reg == CHIP_ANA_CTRL) ana_ctrl = val;
  Wire.beginTransmission(0x10);
  Wire.write(reg);
  Wire.write(val);
  if (Wire.endTransmission() == 0) return true;
  return false;
}

void maxRead(unsigned int reg) {
  Wire.beginTransmission(0x10);
  Wire.write(reg);
  Wire.endTransmission(false);

  int n = Wire.requestFrom( 0x10, byte(1));
  if( n != 1) {
    Serial.println( "requestFrom failed");
  }
  else {
  while(Wire.available()) { // slave may send less than requested
      byte c = Wire.read();   // receive a byte as character
      Serial.print("0x");
      Serial.print(c, HEX);        // print the character
      Serial.print(" ");        // print the character
    }
  }
  
  Serial.println();

}

Now, I am not very proficient with I2S standard yet. Maybe there are some more experienced heads here on the forums that can spot some obvious mistakes right away?

Best,
Miro

[Myreauks]

Aaand never mind, problem solved.

[JayShoe]

Sorry nobody helped. I was interested in this, as this chip is quite nice... But I couldn't come up with anything helpful. What was the issue?

[Myreauks]

Hi!
I hand-soldered the chip and turns out it had solder bridges just on the headphone-pins. It's quite a small chip so no wonder, a pretty big challenge to solder on a normal soldering iron. However, I managed to do it quite nicely with some solder paste.

I have now re-soldered the whole thing and have so far tested line-in, headphones, and speaker out connections to be working. Quite a big success, as my board is completely custom and I have no education in electronics engineering.