delay() timing problem on Atmega64a

[Levent Esen]

I'm using https://github.com/MCUdude/MegaCore for Atmega64a.

There was a timing problem with delay() function which is tested only in Proteus simulation.

I reported that problem in this issue https://github.com/MCUdude/MegaCore

I think that it's an issue of the official Arduino core.

I changed the implementation of delay(ms) function and now the problem is resolved.

Here is the official Arduino core code in wiring.c:

void delay(unsigned long ms)

{

uint32_t start = micros();

while (ms > 0) {

yield();

while ( ms > 0 && (micros() - start) >= 1000) {

ms--;

start += 1000;

}

}

}

And this is my code:

void delay(signed long ms)

{

if (ms > 0)

{

unsigned long start = micros();

unsigned long stop = start + ms * 1000UL;

while (micros() <= stop)

{

yield();

}

}

}

[Cristian Maglie]

Il 22/07/2016 13:40, Levent Esen ha scritto:
> I reported that problem in this issue https://github.com/MCUdude/MegaCore
> I think that it's an issue of the official Arduino core.

Please open an issue on github:
https://github.com/arduino/Arduino/issues/new

and post a *full sketch* that shows the problem.

> I changed the implementation of delay(ms) function and now the problem
> is resolved.

[...snip...]

> void delay(signed long ms)
> {
> if (ms > 0)
> {
> unsigned long start = micros();
> unsigned long stop = start + ms * 1000UL;
> while (micros() <= stop)
> {
> yield();
> }
> }
> }

this implementation doesn't handle roll-over correctly if "stop" value
overflows.

C