Vref doubt

[xxopiumxx]

Regards,

I'm trying to read the frequency of a chain pulses with the CCP module.
The problem is that the max voltage of the pulse is 2.5v. Is there any way in which I could change the reference voltage of the comparator?

And, in another way, if I use the timer 3 -for example- to do the same reading the chain as external pulses, can I change the reference voltage in which the timer 'sees' the pulse?

Thanks for advance.

[Mike Walne]

Probably.

But, you need to tell us more:-

1) PIC.
2) Compiler.
3 etc

Mike

[xxopiumxx]

pic: pic18f2550
comp: pcwhd 4.084

thanks ^^

[Gabriel]

Can't you amplify the signal? op amp? transistor? add a DC bias?

You say comparator but mention CCP (capture/compare/PWM).
Did you mean Schmitt trigger input level? Which one is it?

g
_________________
CCS PCM 5.078 & CCS PCH 5.093

[Mike Walne]

The PIC18F2550 has an analogue comparator module.

Use that to convert your 2.5V signal to a 5V signal.
Then feed comparator output to the CCP module.

Mike