16F877 elapsed time control

[BerkayT]

Hello everyone,

I am pretty new with Pic Programming . I have to measure the time elapsed between V0-V voltages. I am planning to use a POT as an input and display the time on 2x16 display. I am planning to use 16 F877 .


Any ideas?


Thanks

Berkay

[mackrackit]

What are the minimum and maximum times you will be needing to measure?

Will you be needing anything else going on at the same time?

Maybe something like

for X = 1 to 255
pause 10
t = t + 1
do whatever, pot
if whatever =  thisorthat then tCalc
next x
tCalc:
display t

I know, not real code But an idea for you to try.

So if "t" equals 100 , that would mean about a second has passed.

[BerkayT]

This is for my master thesis project.

My time range is between 300 - 700 microseconds . Depending on the elapsed time value i will control the valves.

Thanks for your help

[BerkayT]

how can i start the timer for example when the analog input from the pot is 3 V and stop the timer when it is 5 V ?

thanks

[mackrackit]

loop:
If pot value => 3V then time
goto loop

time:
for X = 1 to 255
pauseus 10
t = t + 1
do whatever, pot
if pot value =  5V then tCalc
next x
tCalc:
display t
goto time

You may want to consider using ADCIN in place of POT.
Notice I changed the example to PAUSEUS.
And someplace around here there is a discussion about code execution time, or just test it to adjust the PAUSEUS.

[BerkayT]

Thanks for your idea,

One more question. How am i gonna define the voltage. I have added a loop like but it didnt work. What can be the problem ?

ADC_READ:

ADCIN 0, ADCINFO
D=ADCINFO*100/51

timeloop:
if D>3 then
T1CON.0=1
if D>=4 then
T1CON.0=0
endif
ELSE
goto timeloop
endif

[BerkayT]

Hi mackrackit

i tried this

loop:
If pot value => 3V then time
goto loop

time:
for X = 1 to 255
pauseus 10
t = t + 1
do whatever, pot
if pot value =  5V then tCalc
next x
tCalc:
display t
goto time

You may want to consider using ADCIN in place of POT.
Notice I changed the example to PAUSEUS.
And someplace around here there is a discussion about code execution time, or just test it to adjust the PAUSEUS.

but it doesnt stop counting for a defined voltage once it is triggered it does not stop for the final voltage.

loop:

adcin 0, adval

If adval => 500 then time
goto loop

time:
for X = 1 to 1023
pauseus 10
t = t + 1
If adval = 1000 then tcalc
next x


tCalc:
LCDOUT $fe, 2,"Time" ,":",DEC t
goto time

Once i stop it i ll adjust the pauseus value
Anything missing? any suggestions?