Interrupts
Interrupts
Interrupts
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
An Example:<br />
We must start our program<br />
with these instructions.<br />
We need to write the<br />
initialization part of the<br />
program and setup the stack<br />
(use of the stack is required<br />
when using interrupts)<br />
Start the initialize the<br />
interrupt: set it up for the<br />
high-to-low transition<br />
Enable the interrupt<br />
1/4/2010<br />
$0000 jmp RESET ; Reset Handler<br />
$0002 jmp EXT_INT0 ; IRQ0 Handler<br />
$0004 jmp EXT_INT1 ; IRQ1 Handler<br />
$0006 jmp EXT_INT2 ; IRQ2 Handler<br />
$0008 jmp EXT_INT3 ; IRQ3 Handler<br />
$000A jmp EXT_INT4 ; IRQ4 Handler<br />
$000C jmp EXT_INT5 ; IRQ5 Handler<br />
$000E jmp EXT_INT6 ; IRQ6 Handler<br />
$0010 jmp EXT_INT7 ; IRQ7 Handler<br />
RESET: initialization instructions<br />
ldi r21,low(RAMEND) ;setup the stack<br />
out SPL,r21<br />
ldi r21,high(RAMEND)<br />
out SPH,r21<br />
ldi r21,obxxxxxx10<br />
out EICRA,r21 ;H-to-L on INT0<br />
ldi r21,0bxxxxxxx1<br />
out EIMSK,r21 ;set INT0 Mask<br />
sei ;set Global Int Mask<br />
the rest of the main program<br />
28
Change language