Difference between revisions of "U23 2008/Beispiele Abend1"
< U23 2008
(New page: = Aufgabe = Die Led an Pin PD7 soll im Sekundentakt blinken. == Loesung in Assembler == #include <avr/io.h> #define __SFR_OFFSET 0 .ORG 0 jmp main →reset vektor: .ORG _...) |
(→Loesung in Assembler) |
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== Loesung in Assembler == | == Loesung in Assembler == | ||
| + | |||
| + | Zum kompilieren im Makefile noch einfuegen: | ||
| + | |||
| + | CFLAGS += -nostdlib | ||
#include <avr/io.h> | #include <avr/io.h> | ||
| Line 62: | Line 66: | ||
escape: | escape: | ||
rjmp loop | rjmp loop | ||
| − | |||
== Loesung in C == | == Loesung in C == | ||
Revision as of 19:38, 18 August 2008
Aufgabe
Die Led an Pin PD7 soll im Sekundentakt blinken.
Loesung in Assembler
Zum kompilieren im Makefile noch einfuegen:
CFLAGS += -nostdlib
#include <avr/io.h> #define __SFR_OFFSET 0 .ORG 0 jmp main /* reset vektor */ .ORG _VECTORS_SIZE main: /* config PD7 as output */ ldi r16, 128 out DDRD, r16 loop: /* 0 OR 0 = 0 1 OR 0 = 1 0 OR 1 = 1 1 OR 1 = 1 */ /* 0 XOR 0 = 0 1 XOR 0 = 1 0 XOR 1 = 1 1 XOR 1 = 0 */ /* ZIEL: PORTD = PORTD XOR 128 */ /* toggle bit for PD7 */ in r17, PORTD ldi r18, 128 eor r17, r18 /* toggle bit 7 */ out PORTD, r17 /* burn 19999996 cycles */ ldi r19, 0 ldi r20, 0 ldi r21, 0 loop2: inc r19 brne compare inc r20 brne compare inc r21 compare: ldi r22, 0 cpi r21, 30 cpc r19, r22 cpc r20, r22 breq escape rjmp loop2 escape: rjmp loop
Loesung in C
#include <avr/io.h>
#include <util/delay.h>
void main(void) {
/* config PD7 as output */
DDRD = _BV(PD7); /* == 1<<7 == 128 */
while(1) {
PORTD ^= _BV(PD7);
uint8_t i;
for (i = 0; i < 76; i++) {
/* wait 4 * 65536 cycles */
_delay_loop_2(0);
}
}
}
