On 10/3/06, Shawn Wilton wrote:

> How do you tell which pin on the ICD chip is GPIO3?  I would think that
> you could use the header outside of your circuit, or that it should at least
> enter debug mode...?

With Pin 3 of the 14-pin -ICD device being mapped to pin 1 of the real
F675, then GPIO3 of the real F675 is pin 4, which is should be pin 6
of the -ICD device.  You can have a look at page 7 of DS51292L.



> I checked VPP and it's being pulled up to at least 13V.  Is that the gpio3
> you're talking about?  Remember this is a header board and not on a 12f675
> since you can't have one on the board.

What do you means with Vpp?  Pin 1 of RJ11?  Note that Pin 1 of RJ11
goes to pin 2 (~ICDMCLR) of the -ICD device, which is NOT GPIO3.

I see there might be some confusion here:  At the -ICD device pin 3 -
pin 6  and pin 9 -pin 12 are meant to be mapped to your target
circuit.  Since you're using external MCLR/GPIO3 (don't confuse this
one with the Vpp/~ICDMCLR), you have to pull it to Vdd.

That is one of the limitation of the -ICD header - we have been ripped
off the right to use internal MCLR :)



Best regards,

-- 
WH Tan
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