tmr0.c (1355B)
1 #include "tmr0.h" 2 #include "util.h" 3 4 #define TMR0_REQ_MAX 2 5 6 struct timer_req { 7 ev_handler handler; /* ISR callback */ 8 uint16_t rate; /* Interval */ 9 uint16_t cnt; /* Current time */ 10 }; 11 12 static void tmr0_isr(void) __interrupt; 13 14 static struct timer_req reqs[TMR0_REQ_MAX]; 15 16 static void 17 tmr0_isr(void) __interrupt 18 { 19 struct timer_req *r; 20 uint8_t i; 21 22 if (INTCONbits.TMR0IF != 1) 23 return; 24 for (i = 0; i < TMR0_REQ_MAX; i++) { 25 r = &reqs[i]; 26 if (r->handler == NULL) 27 continue; 28 if (++r->cnt == r->rate) { 29 r->handler(); 30 r->cnt = 0; 31 } 32 } 33 TMR0 = TMR0_DELAY; 34 /* Clear interrupt flags */ 35 INTCONbits.TMR0IF = 0; 36 } 37 38 void 39 tmr0_init(void) 40 { 41 memset(reqs, 0, sizeof(reqs)); 42 OPTION_REG = 0; 43 OPTION_REG |= TMR0_CLK0 | TMR0_PRESCALAR_256; 44 TMR0 = TMR0_DELAY; 45 INTCONbits.TMR0IE = 1; /* TMR0 Interrupt Enable */ 46 INTCONbits.GIE = 1; /* Global Interrupt Enable */ 47 INTCONbits.PEIE = 1; /* Peripheral Interrupt Enable */ 48 } 49 50 void 51 tmr0_delay_ms(uint16_t t) 52 { 53 while (t--) { 54 while (INTCONbits.TMR0IF == 0) 55 ; /* nothing */ 56 INTCONbits.TMR0IF = 0; 57 TMR0 = TMR0_DELAY; 58 } 59 } 60 61 int 62 tmr0_set_event(ev_handler handler, uint16_t rate) 63 { 64 struct timer_req *r; 65 uint8_t i; 66 67 for (i = 0; i < TMR0_REQ_MAX; i++) { 68 r = &reqs[i]; 69 if (r->handler != NULL) 70 continue; 71 r->handler = handler; 72 r->rate = rate; 73 r->cnt = 0; 74 return (0); 75 } 76 return (-1); 77 }