HAL_Delay is offset by 2ms on the scope

[CLH]

The scope is showing the following code takes 602ms (I'm using the external crystal, so no jitter) this 2ms can be seen on top of any delay I set.

 while (1)

 {

HAL_GPIO_WritePin(GPIOB, profilingPin_Pin, GPIO_PIN_SET);

HAL_Delay(300);

HAL_GPIO_WritePin(GPIOB, profilingPin_Pin, GPIO_PIN_RESET);

HAL_Delay(300);

 }

The toggle of a pin takes 70-80ns so that isn't the issue. I have used the 16MHz clock

which still has the +2ms, and some jitter as expected.

Any insights on this will be greatly appreciated!

[Tesla DeLorean · Accepted solution]

Review the library source code.

Seem to recall it adds one and has +/- 1ms accuracy anyway.

Only required to be at least as long as requested.

If you want tighter resolution use a clock that ticks faster than 1 KHz.​