David Nock wrote:

> I'm currently having a problem trying to set the config bits of a 16F84.
> The setup is as follows : DT001 + TM4 + MPLAB 4.12 + Win95.
> MPLAB will program the program memory ok but will always fail when
> trying to set the config bits. I've set the config in code using __CONFIG
> and also tried setting them in MPLAB. It only seems to be accepting
> RC, CP off, PWRT off WDT on. Is there something I'm overlooking or
> is it likely that the chip is stuffed?

What other bits are you trying to set?  Looking at the data sheet the 14 bit
configuration word for the 'F84 has the following bits available:

Bits 0 & 1 set the Oscillator mode (RC, LP,XT, HS)
Bit 2 sets the WatchDog Timer enabled or disabled
Bit 3 sets the PoWeR up TimEr enabled or disabled
Bit 4 - 13 set Code Protect (all or nothing)

I haven't used the 'F84 but it may only be necessary to change Bit 4 rather
than all the CP bits as per the 'C84.

It may be stating the obvious but if you are using text substitutes for
setting the bits e.g. LP, XT etc then they must be defined before you can
use them with __CONFIG. e.g.  _WDT_ON   EQU     H'3FFF'. The __CONFIG directive
just does a logical AND of your definitions on the CONFIG word to set or
clear the required bits.

Although you can call these bits what you like, check the standard textual
definitions in your 16F84.inc file if you are using one.

Dave B