Some Usage Methods of Seeed Studio XIAO MG24 Sense and Standard

/*
  AnalogReadSerial

  Reads an analog input on pin 0, prints the result to the Serial Monitor.
  Graphical representation is available using Serial Plotter (Tools > Serial Plotter menu).
  Attach the center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/AnalogReadSerial
*/

// the setup routine runs once when you press reset:
void setup() {
  Serial.begin(115200);
  pinMode(PD3, OUTPUT);
  digitalWrite(PD3, HIGH);
}

void loop() {
  int voltageValue = analogRead(PD4);
  float voltage = voltageValue * (5.0 / 4095.0);
  
  Serial.print("Voltage: ");
  Serial.print(voltage, 2);
  Serial.println(" V");
  delay(1000);  // delay in between reads for stability
}

/*
   ArduinoLowPower timed sleep example

   The example shows the basic usage of the Arduino Low Power library by putting the device to sleep for a period of time.
   The device will enter sleep mode for 2000ms. During sleep the CPU is stopped but the RAM retains its contents.

   This example is compatible with all Silicon Labs Arduino boards.

   Author: Tamas Jozsi (Silicon Labs)
 */

#include "ArduinoLowPower.h"

void setup()
{
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
  Serial.println("Sleep with timed wakeup");
}

void loop()
{
  digitalWrite(LED_BUILTIN, LED_BUILTIN_ACTIVE);
  delay(500);
  digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
  delay(500);

  Serial.printf("Going to sleep at %lu\n", millis());
  LowPower.sleep(2000);
  Serial.printf("Woke up at %lu\n", millis());
}

/*
   ArduinoLowPower deep sleep example with external or timed wakeup

   The example shows the basic usage of the Arduino Low Power library by putting the device into deep sleep.
   The device will remain in deep sleep until the sleep timer expires.
   During deep sleep the whole device is powered down except for a minimal set of peripherals (like the Back-up RAM and RTC).
   This means that the CPU is stopped and the RAM contents are lost - the device will start from the beginning of the sketch after waking up.

   This example is compatible with all Silicon Labs Arduino boards.

   Author: Tamas Jozsi (Silicon Labs)
 */

#include "ArduinoLowPower.h"

void setup()
{
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
  Serial.println("Deep sleep timed wakeup");
}

void loop()
{
  digitalWrite(LED_BUILTIN, LED_BUILTIN_ACTIVE);
  delay(500);
  digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
  delay(500);

  Serial.printf("Going to deep sleep for 10s at %lu\n", millis());
  LowPower.deepSleep(10000);
}

/*
   ArduinoLowPower deep sleep example with external or timed wakeup

   The example shows the basic usage of the Arduino Low Power library by putting the device into deep sleep.
   The device will remain in deep sleep until the sleep timer expires.
   During deep sleep the whole device is powered down except for a minimal set of peripherals (like the Back-up RAM and RTC).
   This means that the CPU is stopped and the RAM contents are lost - the device will start from the beginning of the sketch after waking up.

   This example is compatible with all Silicon Labs Arduino boards.

   Author: Tamas Jozsi (Silicon Labs)
 */
#include <Arduino.h>
#include "ArduinoLowPower.h"

#define CS_PIN PA6
#define CLK_PIN PA3
#define MOSI_PIN PA5
#define MISO_PIN PA4

#define READ_DATA 0x03
#define WRITE_ENABLE 0x06
#define PAGE_PROGRAM 0x02
#define SECTOR_ERASE 0x20

void sendSPI(byte data) {
  for (int i = 0; i < 8; i++) {
    digitalWrite(MOSI_PIN, data & 0x80);
    data <<= 1;
    digitalWrite(CLK_PIN, HIGH);
    delayMicroseconds(1);
    digitalWrite(CLK_PIN, LOW);
    delayMicroseconds(1);
  }
}

void writeEnable() {
  digitalWrite(CS_PIN, LOW);
  sendSPI(WRITE_ENABLE);
  digitalWrite(CS_PIN, HIGH);
}

void setup()
{
  //Serial.begin(115200);
  pinMode(PA7, OUTPUT);
  digitalWrite(PA7, LOW);

  pinMode(CS_PIN, OUTPUT);
  pinMode(CLK_PIN, OUTPUT);
  pinMode(MOSI_PIN, OUTPUT);
  pinMode(MISO_PIN, INPUT);

  //SW
  pinMode(PD3, OUTPUT);
  pinMode(PB5, OUTPUT);
  pinMode(PB1, OUTPUT);
  pinMode(PB0, OUTPUT);
  pinMode(PA6, OUTPUT);
  digitalWrite(PD3, LOW); //VBAT
  digitalWrite(PB5, LOW); //RF_SW
  digitalWrite(PB1, LOW); //IMU
  digitalWrite(PB0, LOW); //MIC
  digitalWrite(PA6, HIGH);  //FLASH

  //Serial.println("Deep sleep timed wakeup");
  writeEnable();
  digitalWrite(CS_PIN, LOW);
  sendSPI(0xB9);
  digitalWrite(CS_PIN, HIGH);
}

void loop()
{
  delay(12000);  
  digitalWrite(PA7, HIGH);
  delay(500);

  //Serial.printf("Going to deep sleep for 10s at %lu\n", millis());
  LowPower.deepSleep(600000);
}

#define USER_SW  PC3   // Example pin for user switch

void setup() {
  // Other setup code...

  pinMode(USER_SW, INPUT_PULLUP);
  if (digitalRead(USER_SW) == LOW) {
    Serial.println("Enable to upload new sketch");
    while (true) {
      digitalWrite(LED_BUILTIN, LOW);
      delay(50);
      digitalWrite(LED_BUILTIN, HIGH);
      delay(50);
    }
  }
}