Kyrre Aalerud wrote:

>Hi guys.  I am having a bit of a design issue here.
>Making a logger, I want to use GP3 (MCLR) on a 12F675 for both input and
>ICSP thus needing to feed it 12v.
>If I disable MCLR, do I still need to use a pullup on this pin to make sure
>my circuit starts reliably?
>When the programmer isn't connected the pin would be floating, except for
>when I offload my logger,
>then it would be used as a TTL level input for serial data.
>
>Anyone got experience with this?
>
>Kyrre
>
>
>  
>
I'm pretty sure that if you were using the MCLR\ as reset, there is a 
internal pullup but
since you are using as a signal input, you need to add an external R to VDD.

I'd use 22K-27K.

--Bob

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