MCLR Pin

[mister_e]

As there's no protection diode on this pin, it's high likely to limit/help in case of ESD.

Could be tied to Vdd, or better, assuming your PIC allows it, disable it, and use it as an I/O.

[Darrel Taylor]

The MCLR circuit varies between PIC families.
You should always consult the datasheet for the PIC you are using.

For instance, the 12F683 has an internal pull-up on MCLR, so you don't need anything on that pin when MCLR is enabled.

But when using external circuitry there are two warnings that apply, 1 for pull-up (red box) and 1 for pull-down (Note: ).

[mister_e]

Can't argue against Datasheet, that's for sure... But (cough) let's have some fun and let's play with words a lil bit.

Voltages applied to the MCLR pin that exceed its
specification can result in both MCLR Resets and
excessive current beyond the device specification
during the ESD event. For this reason, Microchip
recommends that the MCLR pin no longer be tied
directly to VDD. The use of an RC network, as shown in

Here's the fun... MCLR IS tied to VDD...

Absolute Maximum Ratings(†)
.....
.....
Voltage on MCLR with respect to Vss .................................................. ............................................. -0.3V to +13.5V

Well OK...max spec for MCLR is set 'round 13 volts... well, if this happen... high likely the PIC will burn way before

[/end smarta55]

[boroko]

Found one of those ghost problems that only seems to occur after days of living with it and finally deciding to go to the Forum and seek and answer....

On my 18F4550, I have been living with 30 second start up times after programming or a reset. As I was typing the question, it occured to me to check if I had put a pull-up on MCLR.....NOPE!

Disabled the reset option and tada! it works just the way the datasheet says it should. Imagine!

Another one for the mental library.
Bo