Added a function to allow inverting the output from a GPIO pin

[invectorlabs]

This allows a user to simply by calling the setPinInvert function to invert the output of a GPIO pin instead of rewriting existing code.... if required =) I am not sure if the function declaration is correctly positioned though so please advice.

[earlephilhower]

Thanks, but could we add the declaration to Arduino.h like the other simple additions that don't need the Arduino-Core API headers to be changed (I try and sync them up every now and then).

Also, a line or two in the docs about this and an example (something simple like blink.ino but with toggling the invert pin) would be much appreciated. It's non-standard so users won't be able to discover it otherwise...

[earlephilhower]

Thanks for the example and docs!

[earlephilhower]

While adding this in pinMode seems fine, I think deleting here will break the case where you have someone else controlling the pin (i.e. tone which uses PIO) and then you stop that process and then digitalWrite. Let me whip up a simple test case...

[earlephilhower]

Yes, this breaks normal functionality. Can you re-add the line?

Simple example blinks after analogWrite with master, remains PWN (connected to PIO) with this patch

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  analogWriteRange(100);
  analogWrite(LED_BUILTIN, 50);
  delay(1000);
  analogWrite(LED_BUILTIN, 70);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
  digitalWrite(LED_BUILTIN, HIGH);
}

void loop() {
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
  digitalWrite(LED_BUILTIN, HIGH);
}

[invectorlabs]

gpio_set_function clears the override register so I will need to save the state somehow. I'll get back....

[earlephilhower]

Yes, this breaks normal functionality. Can you re-add the line?

Simple example blinks after analogWrite with master, remains PWN (connected to PIO) with this patch

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  analogWriteRange(100);
  analogWrite(LED_BUILTIN, 50);
  delay(1000);
  analogWrite(LED_BUILTIN, 70);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
  digitalWrite(LED_BUILTIN, HIGH);
}

void loop() {
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
  digitalWrite(LED_BUILTIN, HIGH);
}