Hello everybody.I want to write a program using PIC18F452&XTAL=20MHZ in
C or mikroC to do the followings;
1.Simultaneously turn a timer on[timer0 or...] to count for 1 sec. and
also count the number of High[transition from H to L] state of the
input signal.
2.Turn a timer on[timer0 or...] for 1 sec. and as soon as a input
signal injected or entered to a PIC pin the timer[timer0
or...]immediately turned off and calculate the time of passed by that
timer.
Would you please help and give me some example codes to write those
programs?
Thanks,
Hallo, I think the guys here dont like to write in english language. I'm not familiar with the PIC you are using, but i try to give you some basic hints: 1st: download an read the datasheet 16F452!!! Do not poll a pin for a transition! It wastes time and blocks the PIC. Use interrupts because some pins of the PIC 16F452 are able to release an interrupt by HL or LH transitions. Possible solution with interrupt released through a transition: Within ISR (interrupt-service-routine) starts a counter from 0 or with a preset to count up or start a counter from a preset down to zero. The preset makes you able to calibrate an exact time, eg from start to overflow, or down to zero example: fosz: 20Mhz workcycles: 20MHz:4=5MHz 1s -> count 5.000.000 workcycles connect TMR1 by Software with workcycles connect the prescaler 1:8 by Software between workcycles and TMR1 Calculate: 5.000.0000Hz : 8 = 625000Hz TMR1 counts max. up to 65536 1/10 sec =625000Hz:10 = 62500Hz Preset TMR1 to 62500 then count down Checkt TMR1 = 0 thats 1/10sec Count this event 10 times -> 1sec and that was it! may be it helps you a little! regards Wil1
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