Need to disable interrupts when setting output pins or modifying registers in order to enforce atomic access

[ElectricRCAircraftGuy]

This:

//FOR SPEED PROFILING WITH OSCILLOSCOPE
//-Don't forget that a direct-port-access write like this takes 2 clock cycles, or 0.125 us, so you have to subtract
//2 clock cycles (NOT 4) from whatever time period you profile with the oscilloscope.
#define PROFILE_PIN2_HIGH   PORTD |= _BV(2)  //write Arduino pin D2 HIGH
#define PROFILE_PIN2_LOW    PORTD &= ~_BV(2) //write Arduino pin D2 LOW

is written incorrectly. |= and &= are NOT atomic operations, so technically interrupts should be disabled and enabled again. Implement a macro which uses a do while loop to automatically do that for me, utilizing the following:

uint8_t SREG_bak = SREG;
cli();
// do your pin change
SREG = SREG_bak;

See here for an example:

	uint8_t oldSREG = SREG;
	cli();

	if (val == LOW) {
		*out &= ~bit;
	} else {
		*out |= bit;
	}

	SREG = oldSREG;

Source: https://github.com/arduino/ArduinoCore-avr/blob/master/cores/arduino/wiring_digital.c

NOTE: do this ANYWHERE in the code you use &= or |=, as NONE of those operations are automatically atomic, so you need to add atomic access guards for all of them to force atomicity.