do u know howto interface an ICD VPP signal without problems? I don't.

Hello

I'm designing an automatic signal switcher for the ICD3 (or clone), to isolate the I/O ports from the programming lines automatically. But i have a problem... that i haven't been able to solve for now.

I need to use my own VPP instead the VPP supplied by the ICD but only when the ICD is going to program so, the ICD VPP is going to trigger the circuit that really supplies the VPP for the MCU. The problem -the only one- is interfacing the VPP in the ICD: each time i try to connect something beyond a resistor (or a capacitor below specified capacitance), the ICD lost the target and starts working erraticly... The idea is having something behaving like (just an example, it really doesn't work but you can get the idea):



Does anyone interfaced successfully the VPP line from the ICD3 without anyproblem? I haven't until now and, furtermore, i burned a ICD3 in the process (don't ask me how i still dunno what happened and looks like a postergeist).

Any suggestion or experience related is welcome.


Thanks in advance