You'd need two such circuits for both SCL and SDA signals. The target power should be enabled as the output needs a pull up resistor R2. I tried to simulate a simplest approach which does not require any modification of the PicKit and could be built as an adapter board. the mosfet based one).Īdding more series resistance could ruin the rise/fall times of the waveform, scoping it while experimenting with the values will show if that's true.Īlso, there are a dedicated bidirectional level translator chips, like the TXS0102 or PCA9617A, both have output enable pins, which could be used to isolate the programmer from the targer when not in use (connect only for the programming/verification period). If this PicKit2 you have will be used as the FV-1 programmer only, i'd just mod it, remove the pull down resistors, add a small adapter board with level shifters (ie. It might be risky for the FV-1, especially if you are going to have the programmer plugged all the time while developing. With the included small series resisors all works fine. I guess, for the main function of the PicKit, which is programming/debugging PICs, their PGD & PGC lines are 5V tolerant. However, the I/O lines are at 5V, since the main PIC is powered with that voltage. Looking at the pickit2 schematic, is seems the Vtarget is fed back to an ADC input and measured.
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