Using PIC as a Low Voltage Meter, need help

[Acetronics2]

Hi, Ioannis

As those files are free to download for every one ... and considering our friend's profile ...

let's give this link without any indiscreet further question ...

http://www.melabs.com/resources/samples.htm

Alain

[Ioannis]

Okie-dokie Alain...

Ioannis

[doable]

Thanks Alian for the information,

I dont want to sound stupid but i have little experance in the PIC world, but have a great thurst to learn. Now with the system i am using are the code examples compatable. I have done enough to have learned that even between different PIC the basic code changes, I dont understand Microchip's reason for that.

I will attemp to write to a PIC16F877A the sample code for the voltage meter, I am sure that i have more questions later on. Thanks again for helping with this!

[skimask]

let's give this link without any indiscreet further question ...

Probably never seen the 'little green book' either...

[Acetronics2]

Hi, Ski

As Mel said ... let's be helpful, ... !!!

Alain

[falingtrea]

One thing you can do is to take away the resistor network on your analog inputs and just put a 1k in place of the 100k(for isolation and input protection). That resistor network is scaling a 0-70v input to a 0-5v in to the PIC.

Then connect a 2 volt source to AN3 to serve as the high voltage ref. To do this you need to set register bits PCFG3-0 to '0001'. This changes the range of the ADC to 0-2V, instaed of 0-5v. You could use a simple resistor divider like 3k/2k or a precision voltage reference like a LMV431 or even a zener diode.

[doable]

Thanks Tim for the info, i will try that and let you know how it worked.