2.2 Digital IO

2.2.1 void pinMode(pin, mode);

• brief: set mode for a particular pin.

• param:

  • pin: digital IO pin index, must be a value between 0 and 19, but 2 ~ 13 is preferred. Normally, pin number should be 0 ~ 13. Analog pins A0 ~ A5 can also be adopted, which is according to number 14 ~ 19.

  • mode: INPUT or OUTPUT, where INPUT is for reading, OUTPUT is for writing.

• return: void.

2.2.2 void digitalWrite(pin, value);

• brief: write value to a particular pin.

• param:

  • pin: digital IO pin index, must be a value between 0 and 19, but 2 ~ 13 is preferred. Normally, pin number should be 0 ~ 13. Analog pins A0 ~ A5 can also be adopted, which is according to number 14 ~ 19.

  • value: HIGH or LOW, where HIGH is for high level voltage, LOW is for low level voltage.

• return: void.

2.2.3 int digitalRead(pin);

• brief: read the digital value from a particular pin.

• param:

  • pin: digital IO pin index, must be a value between 0 and 19, but 2 ~ 13 is preferred. Normally, pin number should be 0 ~ 13. Analog pins A0 ~ A5 can also be adopted, which is according to number 14 ~ 19.

• return: either HIGH(1) or LOW(0), where HIGH is for high level voltage, LOW is for low level voltage.