🛠 GPIO, ADC 16 bits et DAC sur le Nucleo STM32H743ZI : bouton, LED et potentiomètre

What you will build

A hands-on tour of the STM32H743ZI's basic I/O: the board exposes up to 114 GPIO with external interrupt capability through the ST Zio connector (Arduino Uno V3 compatible) and the ST morpho headers, plus serious analog silicon: 3× ADC (16-bit, 36 channels, up to 3.6 MSPS) and 2× 12-bit DAC. We will read the USER button, dim an LED and stream a potentiometer value through the DAC.

Board map (default Zephyr mapping, useful even under Arduino)

• LD1 = PB0, LD2 = PE1, LD3 = PB14 ; USER button = PC13
• ADC example pin: ADC1_INP15 on PA3; DAC example pin: DAC1_OUT1 on PA4
• Arduino SPI1 on PD14/PA5/PA6/PB5 ; I2C on PB8/PB9
• The STM32duino variant exposes 28 analog channels (A0–A27) on this board

Hardware

• 1 Nucleo-144 STM32H743ZI + USB data cable
• 1 potentiometer (wiper to A0, ends to 3V3 and GND)
• 1 jumper wire from PA4 (DAC out) to an oscilloscope probe or a multimeter

Code (STM32duino core, board "Nucleo H743ZI")

const uint8_t BTN  = LED_BUILTIN; // USER button is PC13 on the board; on the
                                  // Arduino header use any free pin vs GND
const uint8_t LED  = LED1;        // LD1 = PB0 via the core alias
const uint8_t POT  = A0;          // one of 28 analog channels A0..A27
const uint8_t DAC1 = A4;          // PA4 = DAC1_OUT1 (Zephyr mapping)
                                  // > 
                                  // pin alias depends on your core version

void setup {
  pinMode(LED, OUTPUT);
  Serial.begin(115200);           // ST-LINK virtual COM port
}

void loop {
  int raw = analogRead(POT);      // 3x 16-bit ADCs, up to 3.6 MSPS
  // Map the ADC reading onto the 12-bit DAC output scale
  analogWrite(DAC1, map(raw, 0, 4095, 0, 255));
  digitalWrite(LED, (raw > 2048) ? HIGH : LOW);
  Serial.printf("ADC=%d  -> DAC level=%d\n", raw,
                map(raw, 0, 4095, 0, 255));
  delay(100);
}

Steps

1. Wire the potentiometer between 3V3, GND and A0 (never feed more than the board's own rail into a pin).
2. Select board Nucleo H743ZI in the STM32duino core and upload.
3. Turn the pot: the multimeter on PA4 should follow smoothly — that is the 12-bit DAC working.
4. Press the USER button (PC13) if you wired it to a header pin: use pinMode(pin, INPUT_PULLUP) and digitalRead the same way.

Expected result

ADC counts climb while you turn the pot, the DAC voltage follows, and LD1 flips at mid-scale. With three 16-bit ADCs at up to 3.6 MSPS, this board samples far faster than any classic Arduino — the bottleneck is your sketch, not the silicon.

Common pitfalls

• ZI vs ZI2: the two Nucleo boards wire the Arduino header differently — pick the exact board you own or every D/A number is silently remapped.
• Reading A0 while the Zephyr mapping says ADC1_INP15 is PA3: Arduino numbers and ST signal names are two different namespaces ; check the variant file for the mapping.
• Forgetting that the 16-bit ADC may be configured at lower resolution by default in some cores — check the ADC example in STM32CubeH7's Examples/ADC for full-control setups.