PIC Vietnam > Microchip PIC > Cc ngn ng lp trnh khc (CCS C, HT PIC,...) > ngt timer CCS PDA View Full Version : ngt timer CCS hunter800 22-03-2010, 02:37 PM hix ai gii thch dm mnh chng trnh ngt ny vi!Mnh thc s rt c gng c nhng chu hiu lm!thanks #include #fuses NOWDT,PUT,XT,NOPROTECT #use delay(clock=4000000) #byte PORTB = 0x06 int16 count; int8 a; //Chuong trinh ngat TMR0 #int_timer0 void interrupt_timer0() { set_timer0(6); ++count; if(count == 2000) // 2000*500us = 500000us = 1s { count=0; rotate_left(&a,1); } } //Chuong trinh chinh void main(void) { set_tris_b(0); enable_interrupts(int_timer0); setup_timer_0(RTCC_INTERNAL|RTCC_DIV_2); enable_interrupts(global); set_timer0(6);// T_dinhthi = 2*(256 - 6)*1us = 500us a = 0x01; while(true) { PORTB = a; } } trai_xq

22-03-2010, 05:00 PM hix ai gii thch dm mnh chng trnh ngt ny vi!Mnh thc s rt c gng c nhng chu hiu lm!thanks #include #fuses NOWDT,PUT,XT,NOPROTECT #use delay(clock=4000000) #byte PORTB = 0x06 int16 count; int8 a; //Chuong trinh ngat TMR0 #int_timer0 void interrupt_timer0() { set_timer0(6); ++count; if(count == 2000) // 2000*500us = 500000us = 1s { count=0; rotate_left(&a,1); } } //Chuong trinh chinh void main(void) { set_tris_b(0); enable_interrupts(int_timer0); setup_timer_0(RTCC_INTERNAL|RTCC_DIV_2); enable_interrupts(global); set_timer0(6);// T_dinhthi = 2*(256 - 6)*1us = 500us a = 0x01; while(true) { PORTB = a; } } +set_tris_b(0);//nh ngha portb l u ra s(nu nh vng lp while bn khai bo output_b(a); th cu lnh set_tris_b(0); l khng cn thit. +enable_interrupts(int_timer0);//mi bt u chng trnh, bn cho timer0 lm vic(bt u tnh +setup_timer_0(RTCC_INTERNAL|RTCC_DIV_2); //ch l chia tn s timer0 8bit, m t 0-->255, v sau trng m li t 0. Mi ln trn nh vy l c bn tnh thi gian nh sau: -bn dng thch anh 4M=4000000hz. nh vy mi ln trn th c thi gian l

Ttimer0=255*4/(4.000.000) (s)=255micro s. Nhn 4 bi v mt chu k lnh ca VDk=4 chu k xung ca thch anh. Mc ch ca chng ta l to ra mt giy, nh th th phi lm sao? +setup_timer_0(RTCC_INTERNAL|RTCC_DIV_2); //lnh ny s nng gii tn ca timer0 ln 2 ln na. ngha l khi c ln ny ttimer0 s c tnh li sau mi ln trn nh sau: Ttimer0=( 255*4/(4.000.000) )* 2(s) = 510micro s +enable_interrupts(global);//cho ngt ton b(lnh ny khng cn nu nh bn ch c ngt timer0) +set_timer0(6);//t gi tr u cho timer0 l 6, ngha l timer by gi tng t 6 ch khng phi l 0 na. Ch ny thi ti ngh c s nhm ln l set_timer0(5); l ng hn, v sao phi lm vy bn bit khng? tt ca cng ch v cho d tnh v chn s thi. Nu t nh vy th thi gian timer0 s c tnh li nh sau: Ttimer0=( (255-5)*4/(4.000.000) )* 2(s) = 500micro s +nh vy bn phi cn my ln trn mi c 1s? c phi l 2000 ln khng v 2000*500=1000000micro s=1s ok! +on chng trnh ny s th vn : #int_timer0 void interrupt_timer0() { set_timer0(5); ++count; if(count == 2000) // 2000*500us = 500000us = 1s { count=0;//nu c 2000 nghn ln trn( c 1s) th cho trn li t u rotate_left(&a,1);//tng ng vi lnh a=a