Posted on October 07, 2016 at 15:06Hi,
I have just started with STM8 and would like to found the fastest toggling method.
Currently I have best result with following code:
while (1)
{
#pragma asm
push A
pushw X
ld A, #1 // toggle with pin D0
ldw X, #0x500f // GPIOD (port D output latch)
clr (X)
ld (X), A
clr (X)
ld (X), A
clr (X)
ld (X), A
clr (X)
ld (X), A
clr (X)
ld (X), A
clr (X)
ld (X), A
popw X
pop A
#pragma endasm
}
The block of 6x CLR / LD makes ''bit clear'' / ''bit set''.
Size of both instructions is 1 byte, so fetching shouldn't cause any delay.
The result is Low 62.5ns / High 125ns (i.e. 1c/2c @16MHz), repeating 6x.
I don't understand why the 1c/1c toggling is not achieved.
I would like to ask for explanation of this and solution for 1c/1c toggling (if possible).
Thanks
