How do I release my pins?

guotingchao commented 5 years ago

now, i release these pins

clearServePin() {
    new Gpio(this.STEER_PIN, {mode: Gpio.PUD_OFF});
  }

Always feeling embarrassed, so what should be the right approach?

fivdi commented 5 years ago

I'm not 100% sure what "releasing a pin" means here but I think it means "how do I get a pin back into the mode it was in before my program started?".

If this is the case, then the pigpio Gpio methods mode and pullUpDowncan typically be used to return the pin to the mode it was in before a program started.

For example, when a Raspberry Pi is booted, GPIO17 is configured as an input and it's pull-down resistor is activated. Lets say you have an LED connected to GPIO17 and a program that configures GPIO17 as an output and turns the LED on. The following program uses the mode and pullUpDown methods to return GPIO17 to the appropriate mode before terminating:

const Gpio = require('pigpio').Gpio;

// Create a Gpio object for the LED on GPIO17.
const led = new Gpio(17, {mode: Gpio.OUTPUT});

// Turn LED on.
led.digitalWrite(1);

// Wait 2 seconds before terminating the program.
setTimeout(() => {
  // Reconfigure GPIO17 as an INPUT
  led.mode(Gpio.INPUT);

  // Activate the pull-down resistor on GPIO17.
  led.pullUpDown(Gpio.PUD_DOWN);
}, 2000);

guotingchao commented 5 years ago

@fivdi Tks, You solved my confusion.

fivdi / pigpio

How do I release my pins? #77