On Fri, 11 Jun 2004 10:49:25 -0400, you wrote:

>The programming pin needs to accept high voltages at any time=20

>If you want the devices built such that programming is fool proof (ie,
>the uC will never be in a state where programming cannot take place)
>then yo

That's not strictly true - the programming spec could insist that MCLR =
goes high within, say 4uS of
Vdd being applied. That way, the pin would be guaranteed to be an input =
when Vpp is applied, and
this ought to make it compatible with at least an open-drain output - I =
can see issues with making
it a 'proper' output due to reverse biasing issues of the P-side driver, =
but an open drain output
would be a lot more useful than input-only.

The 8-pin devices already have some constraints about Vdd/Vpp sequencing =
etc., so it shouldn't be
incompatible with existing programmer hardware.

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