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96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
15 years ago
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#include "avr/io.h"
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#include "util/delay.h"
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#include "pt.h"
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/* Two flags that the two protothread functions use. */
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static int protothread1_flag, protothread2_flag;
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static int
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protothread1(struct pt *pt)
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{
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/* A protothread function must begin with PT_BEGIN() which takes a
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* pointer to a struct pt. */
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PT_BEGIN(pt);
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/* We loop forever here. */
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while(1) {
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/* Wait until the other protothread has set its flag. */
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PT_WAIT_UNTIL(pt, protothread2_flag != 0);
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PORTB |= _BV(PB3);
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_delay_ms(200);
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PORTB &= ~_BV(PB3);
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_delay_ms(200);
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/* We then reset the other protothread's flag, and set our own
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flag so that the other protothread can run. */
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protothread2_flag = 0;
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protothread1_flag = 1;
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/* And we loop. */
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}
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/* All protothread functions must end with PT_END() which takes a
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* pointer to a struct pt. */
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PT_END(pt);
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}
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static int
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protothread2(struct pt *pt)
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{
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/* A protothread function must begin with PT_BEGIN() which takes a
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pointer to a struct pt. */
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PT_BEGIN(pt);
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/* We loop forever here. */
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while(1) {
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/* Let the other protothread run. */
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protothread2_flag = 1;
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/* Wait until the other protothread has set its flag. */
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PT_WAIT_UNTIL(pt, protothread1_flag != 0);
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PORTB |= _BV(PB2);
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_delay_ms(100);
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PORTB &= ~_BV(PB2);
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_delay_ms(100);
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/* We then reset the other protothread's flag, and set our own
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flag so that the other protothread can run. */
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protothread1_flag = 0;
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protothread2_flag = 1;
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/* And we loop. */
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}
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/* All protothread functions must end with PT_END() which takes a
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* pointer to a struct pt. */
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PT_END(pt);
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}
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static struct pt pt1, pt2;
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int main() {
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// pin 11 = PB3
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DDRB |= _BV(PB3);
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// pin 10 = PB2
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DDRB |= _BV(PB2);
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/* Initialize the protothread state variables with PT_INIT(). */
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PT_INIT(&pt1);
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PT_INIT(&pt2);
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/*
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* Then we schedule the two protothreads by repeatedly calling their
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* protothread functions and passing a pointer to the protothread
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* state variables as arguments.
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*/
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while(1) {
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protothread1(&pt1);
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protothread2(&pt2);
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}
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}
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