Yes that's right,

everytime you call ON/OFF/RESETPORTS routines they terminate with a ret instruction that puts your stack where it was before calling them.

But you are also calling loop which is never terminating with a ret, so your stack grows on and on and overflows.

But it should run more than 4 times..........


LOOP:

acall ON
acall OFF
acall RESETPORTS
acall LOOP
====================
ON
...
...
...

RET
====================
OFF
...
...
...

RET
====================
RESETPORTS
...
...
...

RET
====================