| ??? 08/12/09 07:28 Read: times |
#168332 - 8 bit auto reload |
I have connected a LED to p1.4 and the below code glows the LED for some ms and turns off. The time delay is close to 1 sec, plz tell me how can i make it exact 1 second time delay. It is a 8 bit auto reload timer mode.
$mod51 LED EQU P1.4 org 0000h MOV TMOD,#20h ;Timer0 8-bit Auto Reload Mode loop: MOV R3,#250H CH: MOV TH0,#00h CLR LED ;Turn ON LED SETB TR0 ;Start Timer 0 JNB TF0,$ ;Wait till Timer 0 overflows CLR TF0 ;Timer0 has overflowed clear the Flag CLR TR0 ;Stop Timer0 DJNZ R3,CH SETB LED ;Turn OFF LED SETB TR0 ; Start Timer 0 JNB TF0,$ ;Wait till Timer 0 overflows CLR TF0 ;Timer0 has overflowed clear the Flag CLR TR0 ;Stop Timer0 ajmp loop END |
| Topic | Author | Date |
| 8 bit auto reload | 01/01/70 00:00 | |
| what crystal frequency? | 01/01/70 00:00 | |
| 11.05 Mhz | 01/01/70 00:00 | |
| be precise | 01/01/70 00:00 | |
| what happen at MOV R3,#250H | 01/01/70 00:00 | |
250 | 01/01/70 00:00 |