Using 16LF88 at 3 volts?

[adamthole]

Hello,

I am familiar with the PIC16F88 and have been using at at 5 volts for a while. I am working on a new application that runs off of around 3 volts. From reading the data sheet I realized that I need to get the 16LF88 in order to run it at 3 volts. I am now using the LF88 and I still cannot get it to run at 3 volts. It does not work until I give it around four volts.

My guess is that my oscillator is configured incorrectly to work off of this low voltage. I am currently running it off of the int_rc at 8 MHz.

osccon = 01110000b;

Right now my best guess is that I need to re-program it to run at 4 MHz, but thought I would check with you guys before I waste my time when it may be something else. (It is currently SMD in circuit, and I don't have ICSP pins on the board)

Thanks!

 

[kchriste]

Right now my best guess is that I need to re-program it to run at 4 MHz,

Your guess is correct.

 

[adamthole]

Okay, thanks. It is confusing, because there is a chart in the data sheet that says you can run it up to 10MHz at 3 volts, but I guess that is for some sort of external oscillator configuration.

 

[kchriste]

Just looked at the datasheet and yes, it does look like it should run at 10Mhz between 3.0V and 5.5V
The other thing that could cause this would be if you have the brownout reset enabled. It activates at 4V and below....

 

[adamthole]

Thanks kchriste, it was the brownout reset. Works like a charm now!