Frequently Asked Questions

Why isn't PortB, pin 3, working?

I write to the port by using :

#byte portb 0x06
	
portb=0xff

All pins on portB for high, except for pin3. What's wrong here?

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Topic posted by Peter Smith on the user forums, April 28, 2000.

I'm guessing here that you're using an 16F87X. I had no end of problems with this device until I read the manual. I then found that B3 is linked with the low voltage programming feature, and if you have LVP enabled, you can't use B3 (and a few others).

You'll find that if you use something like

#fuses xt,nowdt,noprotect,put,nowrt,nolvp

everything will start working. The nolvp bit at the end is the most important.