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Step 2ICSP port
Make an ICSP port with part of a chip socket, like this. Carefully bend the pins at a right angle.
Now glue port down.
Now is also a good time to glue your transistors on. You can also solder the emitter of your npn transistors to the ground plane, now. I have labelled each transistors purpose here.
The three npn transistors will be wired as inverters. They will essentially "take power away" from their respective pullup resistor when a current is placed onto their base pin.
The PNP transistor (upside down) will control the programming voltage. It is also going to invert it's signal.
**EDIT: I just realized an omission in this design. There should be one additional npn transistor that is used to drive the PNP transistor. This will buffer your computer port from the voltages at the pnp's base. My bad. This will also uninvert the signal. See step 8.
Now glue port down.
Now is also a good time to glue your transistors on. You can also solder the emitter of your npn transistors to the ground plane, now. I have labelled each transistors purpose here.
The three npn transistors will be wired as inverters. They will essentially "take power away" from their respective pullup resistor when a current is placed onto their base pin.
The PNP transistor (upside down) will control the programming voltage. It is also going to invert it's signal.
**EDIT: I just realized an omission in this design. There should be one additional npn transistor that is used to drive the PNP transistor. This will buffer your computer port from the voltages at the pnp's base. My bad. This will also uninvert the signal. See step 8.
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