Digital I/O

The Quarto has eight digital input and output pins, which can be utilized using standard Arduino™ functions:

• pinMode
• digitalWrite
• digitalToggle
• digitalRead

pinMode

void pinMode(uint8_t pin, uint8_t mode);

This function configures the input or output characteristics of a digital pin. By default, all pins are inputs. The function takes the following arguments:

• pin Pin should be an integer between 1 and 8, corresponding pins D1 through D8.
• mode sets the input or output mode. Valid options are:
  • OUTPUT: Standard output pin (3.3 V CMOS push-pull)
  • OUTPUT_OPENDRAIN: Open drain output
  • INPUT: Standard input (floating)
  • INPUT_PULLUP: Input with 22 k pull-up resistor
  • INPUT_PULLDOWN: Input with 100 k pull-down resistor

Example

pinMode(1,OUTPUT);
pinMode(2,INPUT);

digitalWrite

void digitalWrite(uint8_t pin, uint8_t value);

This function sets a digital output pin HIGH or LOW. Unlike in many Arduino™ systems, there is no need to use digitalWriteFast() for better speed performance as digitalWrite() has already been optimized for speed. The function takes the following arguments:

• pin Should be an integer between 1 and 8, corresponding to pins D1 through D8.
• value Sets the pin to 0 or 1. Valid options are:
  • LOW
  • HIGH

Example

void setup() {
	pinMode(1,OUTPUT);
    pinMode(2,OUTPUT);
}

void loop() {
	digitalWrite(1,HIGH);
    digitalWrite(2,1); // same as digitalWrite(2,HIGH)
	digitalWrite(1,LOW); 
    digitalWrite(2,0); // same as digitalWrite(2,LOW)
}

digitalToggle

void digitalToggle(uint8_t pin);

This function toggles the state of a digital output pin HIGH or LOW. Unlike in many Arduino™ systems, there is no need to use digitalToggleFast() for better speed performance as digitalToggle() has already been optimized for speed. The function takes the following argument:

• pin Should be an integer between 1 and 8, corresponding pins D1 through D8.

Example

void setup() {
	pinMode(1,OUTPUT);
	pinMode(2,OUTPUT);
}

void loop() {
	digitalToggle(1);
	digitalToggle(2);
}

digitalRead

uint8_t digitalRead(uint8_t pin);

This function returns 0 if the digital input pin is low and returns 1 if the digital input pin is high. Unlike in many Arduino™ systems, there is no need to use digitalReadFast() for better speed performance as digitalRead() has already been optimized for speed. The function takes the following arguments:

• pin Should be an integer between 1 and 8, corresponding pins D1 through D8.

Example

void setup() {
	pinMode(1,INPUT);
    pinMode(2,INPUT);
    pinMode(3,OUTPUT);
    pinMode(4,OUTPUT);
}

void loop() {
	if ( digitalRead(1) ) {
	    //D1 is high
        digitalWrite(3,LOW);
	} else {
    	if (digitalRead(2) == LOW) {
            //D1 and D2 low
            digitalWrite(4,HIGH);
        } else {
            //D1 low, D2 high
            digitalWrite(4,LOW);
        }
    }
}