12F675/629 question

Started by Phil March 29, 2004
I'm trying to use the MCLR pin for I/O on this device. The data
sheet claims to do so you clear the MCLRE config bit. When I do
this the device behaves very oddly (output pins go to Vdd) and it
almost looks like a reset that only half happened but not exactly.
I'm using INTOSC (with no clock out). Also, no BOD, no WDT, no LVP
set.

There is a somewhat cryptic footnote in the datasheet section on the
MCLRE config bit that says "When MCLR is asserted in INTOSC or RC
mode, the internal clock oscillator is disabled." Are they trying to
say that you can't use INTOSC and turn MCLR into a GPIO pin at the
same time? If so, I'm kinda pissed as that leaves me with 5 pins,
not 6.

Anyone ever got INTOSC and MCLRE=0 to work at the same time?

Given that it costs $1, I plan on using it a bunch so I guess I cant
be too mad ...

Phil



--- In , "Phil" <phil1960us@y...> wrote:
> I'm trying to use the MCLR pin for I/O on this device. The data
> sheet claims to do so you clear the MCLRE config bit. When I do
> this the device behaves very oddly (output pins go to Vdd) and it
> almost looks like a reset that only half happened but not exactly.
> I'm using INTOSC (with no clock out). Also, no BOD, no WDT, no LVP
> set.
>
> There is a somewhat cryptic footnote in the datasheet section on
the
> MCLRE config bit that says "When MCLR is asserted in INTOSC or RC
> mode, the internal clock oscillator is disabled." Are they trying
to
> say that you can't use INTOSC and turn MCLR into a GPIO pin at the
> same time? If so, I'm kinda pissed as that leaves me with 5 pins,
> not 6.
>
> Anyone ever got INTOSC and MCLRE=0 to work at the same time?
>
> Given that it costs $1, I plan on using it a bunch so I guess I
cant
> be too mad ...
>
> Phil

Phil,

I have used the 12F629 with INTOSC and internal MCLR on several
occasions without incident. I haven't read that statement in the
manual but I could have an older version of the manual.

Mike


I've used MCLR as I/O w/ the intosc on 12F629's and 675's. Didn't use
the internal pullups or analog on any I/O.

--- Phil <> wrote:
> I'm trying to use the MCLR pin for I/O on this device. The data
> sheet claims to do so you clear the MCLRE config bit. When I do
> this the device behaves very oddly (output pins go to Vdd) and it
> almost looks like a reset that only half happened but not exactly.
> I'm using INTOSC (with no clock out). Also, no BOD, no WDT, no LVP
> set.
>
> There is a somewhat cryptic footnote in the datasheet section on the
> MCLRE config bit that says "When MCLR is asserted in INTOSC or RC
> mode, the internal clock oscillator is disabled." Are they trying to
>
> say that you can't use INTOSC and turn MCLR into a GPIO pin at the
> same time? If so, I'm kinda pissed as that leaves me with 5 pins,
> not 6.
>
> Anyone ever got INTOSC and MCLRE=0 to work at the same time?
>
> Given that it costs $1, I plan on using it a bunch so I guess I cant
> be too mad ...
>
> Phil


__________________________________