finished my pic programmer!

i finally finished my high-voltage pic programmer and tested it out. i used ian's icsp jdm2-style design, with a few modifications: 1. i made a one-sided board with 3 jumpers. (ian mentions this variant; i think he designed it to be easy to do one-sided.) 2. i use alligator clips instead of header pins. 3. most significantly, i used a stack of diodes in place of the 8v2 zener. radio smack didn't have an 8v2, and i didn't want to pay s&h for a $.30 part. so i used a 5v1 zener, an led, an ordinary silicon diode, and a 100ohm resistor in series. that puts the programming voltage right in the 12-13v sweet spot, and the led gives me a nice programming activity indicator. i tried it out on a 16f877a and a 18f458 with picprog. my dell laptop couldn't muster the 12v for burning, but it can read them okay. the desktop could also read just fine, but i had problems burning the chips while they were in a breadboard. i could barely limp with a little blink-an-led test program by repeatedly burning without erasing. each time it would write a few more bytes before failing to verify. when i tried it on a 16f877a that i had soldered into a perf board, though, it worked perfectly. first time, every time. lesson learned: breadboards are evil. when i tried out the blink-an-led on the breadboard, i couldn't get a stable clock. that's not too surprising, considering i was using a 20MHz crystal. but i didn't think that nasty capacitance was so bad that couldn't even use the relatively low-speed programmer. oh, well. now that i'm used to soldering, i don't really see an advantage to the breadboard anymore. i think the easiest way to do it is to solder the pic in first, program it, then solder other components and test along the way.