PIC sinking voltages higher that Vdd???

[Darrel Taylor]

Hmmm, well I guess it depends on which PIC you are looking at.
manumenzella never specified. And the original post regarding RA4 as much as assumed they are ALL like that.

Paul was referencing the 16F628, which according to the most recent datasheet, Has the diode.

If you look at a 16F628A, then it doesn't.

If you look at the 18F452 datasheet from a couple years ago, it says it does, but the most recent one doesn't.
Was it a change in the datasheet, or the silicon?

Like my original comment,
"Which one are we supposed to believe?"

Personally, I'd go with the transistor.
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[Acetronics2]

Hi, Picmen

Pic Inputs clamp Diodes are rated @ 500µA ...

So, applications that limit the input current @, say 50µA ( good safety margin !!! ) can be done.

That includes sensing Mains through a 4.7 MOhm 1/2 W or 2 x 2.2 MOhms 1/4W in series ( care to the max voltage across the 1/4W resistors : 250 v PEAK )

I have built lots of 8 Pïns Pics working on mains as zero voltage switches or dimmers ...

BUT Remember TOCKI or MCLR pins DO NOT HAVE the VCC Clamp diode : an external diode has to be added then ...
and it's no pain if a clamp diode is already built in the package !!!

Alain

[Ioannis]

Personally, I'd go with the transistor.
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I double that Darrel. That's what I always do and keep my headaches far away...!

As for the datasheets, they may have errors. Some are found, some not. What about the errata? I have not time to look right now.

Ioannis

[sougata]

Hi,

Spending on a single NPN transistor and a couple of resistor do give you the flexibility to use any pin without the need for painkillers.