Serial Ports

Serial Ports

The Edge101 board has three serial ports: Serial, Serial1, and Serial2.

• Serial is connected to the USB interface for program downloading and code debugging. It will output basic information about the board upon power-up.
• Serial1 is used to extend the onboard wireless module or external serial devices.
• Serial2 is used for RS485 interface to connect industrial sensors, actuators, and other devices.

Example: Serial Read of User Button State

The following code demonstrates the functionality of reading the digital input signal from pin 38 and outputting the result to the serial monitor.

Hardware Preparation:

• ESP32 IoT Programmable Controller (SKU: DFR0886)×1

Sample Code:

/* Digital Input Read Example */
int pushButton = 38;

// Initialization function (runs once on reset):
void setup() {
  // Initialize serial communication at a baud rate of 115200:
  Serial.begin(115200);
  // Set the button pin as input:
  pinMode(pushButton, INPUT);
}

// Main loop function (runs repeatedly):
void loop() {
  // Read the state of the input pin:
  int buttonState = digitalRead(pushButton);
  // Output the button state to the serial monitor:
  Serial.println(buttonState);
  delay(1);        // Delay to ensure stable reading
}

Result:
When the onboard user button is not pressed, the serial monitor will display 1. When the button is pressed, the serial monitor will display 0.