![]() ![]() I just realized that these two resistors will form a voltage divider, and if each is 10k data high will be 2.5V. Also, data out tranny should not be pulled up with the 10k resistor network. **EDIT: the base resistor for the 'data in' tranny should be 22k. I messed up the pnp transistor in this pic. This will buffer your computer port from the voltages at the pnp's base. There should be one additional npn transistor that is used to drive the PNP transistor. **EDIT: I just realized an omission in this design. The PNP transistor (upside down) will control the programming voltage. They will essentially 'take power away' from their respective pullup resistor when a current is placed onto their base pin. The three npn transistors will be wired as inverters. I have labelled each transistors purpose here. You can also solder the emitter of your npn transistors to the ground plane, now. Now is also a good time to glue your transistors on. Carefully bend the pins at a right angle. Make an ICSP port with part of a chip socket, like this. ![]() You need: A male DB25 socket 4x NPN transistors, such as the 2n3904 1x PNP transistor, such as the 2n3906 1x 7805 voltage regulator 1x LM317 voltage regulator (and appropriate resistors to make 12.5V) 1x 10k SIP resistor network 4x 10k resistors 1x 22k resistor* update for step 3 1x 5k resistor 1x 1k resistor* update for step 3 1x machined-pin chip socket soldering iron, protoboard, wraping wire, wrapping tool, glue gun. See step 7 for pics of the software I use and how to set up the programmer. These changes are already reflected in this list, but are not updated in all the pics. ![]() I had to add an additional npn transistor and change a couple of resistor values. I have built several variations, and I thought I was on top of things.:) There are a couple of changes, but everything worked out in the end. Click the smaller images below! ** This is a new variation and it didn't work 100% correctly on the first attempt. Best of all, it uses just two voltage regulator and 5 transistors! *** I added a pic of the final result, and pics of my new mini-programmer with a clear top. This project presents a JDM serial programmer to work with modern PIC families that require VCC control. It is very reliable and there is good programming software available for free. This is a variation of David Tait's classic design. Make your own PIC programmer for your computer's parallel port. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |