AVR128DA64 Analog output setup

[seaspac]

Unable to set up the DAC for AVR128DA64 chip, tried to configure but could not get any output it's always 4.2Volts on PD6, I have put 56K as load resistor tied to ground, need an example code to properly setup DAC0 analog output which is going to be used as contrast setting for 4 X20 LCD. Idea is to use DAC0 analog output voltage as digital control of contrast of LCD

[westfw]

Using Spence Konde’s Arduino core? Or bare c?
What does your current code look like?

[seaspac]

using dxcore from Spence konde's, but there is no clear example how to proceed I tried different methods but does not work. using following code not sure if its correct but its not working.

unsigned int dacValue = 0;

void setup() {
  
Serial.begin(115200); // open the serial port
DACReference(VDD); 
DAC0.CTRLA |= (DAC_OUTEN_bm | DAC_ENABLE_bm);
dacValue = 512;
// write value to DAC
DAC0.DATA   = (dacValue << 6); // this should produce some voltages according to dacvalue on PD6 pin.

}

void loop() {


}

[westfw]

DxCore should have Arduino-style support for the DAC

   analogWrite(PIN_PD6, value);  // output 8bit analog value

As for your own code. Did you do:

The input for the DAC pin must be disabled in the Port peripheral (ISC = INPUT_DISABLE in PORTx.PINCTRLn).

[seaspac]

Thanks "westfw", I knew from the datasheet that DAC output pin needs to disable input but was not sure how to do it, after a bit of research found the method now the DAC is working fine posting the code I tested below.

unsigned int dacValue = 0;

#define PIN_ISC_DISABLE      0x00C0 // DISABLED

void setup() {
  
Serial.begin(115200); // open the serial port

PORTD.PIN6CTRL = PIN_ISC_DISABLE;

DACReference(INTERNAL2V5); 
DAC0.CTRLA |= (DAC_OUTEN_bm | DAC_ENABLE_bm);
dacValue = 512;// 0 - 1023 10bit data will produce 0 - 2.5V on DAC0 out put pin 

DAC0.DATA   = (dacValue << 6); // this should produce some voltages according to dacvalue on PD6 pin.

}

void loop() {

Serial.println(DAC0.DATA);
delay(3000);
}