simpsonss 
hi all.
My asm code just to blink the leds. For my first code, i didnt add in the load stack step which is as follow:
ldi R16,low(RAMEND) out SPL,R16 ldi R16,high(RAMEND) out SPH,R16
the LEDs wont blink.But once i add in these steps.it works and start to blink.
From what i had experience with other chip like M**rochip.the asm code dont have to consider about this when applying subroutine. So can anyone explain why could this happen?
thank you.
js 
Newer AVRs set up the stack for you at power up like M**rochip :shock: but you MUST set up the stack yourself for older AVRs. PICs only have a limited stack anyway.
It is a good habit to setup the stack even if the hardware does it for you, it will save you headache when you change chips or brand of chips.
simpsonss hi js,
thanks for the reply.I'm using ATmega32L for my testing.As what i know, ATmega32L should be not included in older AVR list.Or is it?
because when i quote the four instruction steps, the leds wont manage to blink.But yes if i add in.So is it ATmega32L is older AVR?
thank you.
js ATmega32L should be not included in older AVR list.Or is it?
simpsonss hi js,
but if i wrote the blinking code in C.i wont have to worry about this steps.it will work without take care of the load stack part.Any idea what happen in C?
thank you.
stevech If you have no subroutines or interrupts (yet), you probably don't need a stack.
If you show the entire program, and perhaps how you are linking it and downloading it, perhaps we can solve the problem.
That code segment you posted doesn't show the org or the loop and delay between toggling the LED.
The beginners' tutorials here would help.
simpsonss hi,
thanks for the reply again.
.include "m32def.inc" .def temp= r19 rjmp start start: ldi R16,low(RAMEND) out SPL,R16 ldi R16,high(RAMEND) out SPH,R16 ldi temp,0xff out DDRB, temp loop: ldi temp,0x00 out PORTB,temp rcall delay ldi temp,0xFF out PORTB,temp rcall delay rjmp loop delay: ldi R16,0xff loop1: ldi R21,0xff loop2: dec R21 brne loop2 dec R16 BRNE loop1 ret
above is my blinking asm code.
simpsonss Quote:Yep,pretty old in micro years. :) Use a Mega324p.ATmega32L should be not included in older AVR list.Or is it?
hi js,
thanks for this info.After comparing the price.The newer avr is much more cheaper than the oldest avr.thanks.
Koshchi but if i wrote the blinking code in C.i wont have to worry about this steps.it will work without take care of the load stack part.Any idea what happen in C
stevech If you have masochistic tendencies, you may write the application in assembly language.
