Anybody still using parallel PIC pgmers?

[prschmitt]

Hi, Folks!
This is my first post! Yay!
I've been lurking and learning for a while, so I figured for a first post, I could hopefully give something back.

I've been preparing to tinker around with a  PGA2505 using a PIC16F877a to talk to it (yes, I've seen Igor's work, but sometimes you just want to do it yourself  ) and thought someone might find some use for a brute-force parallel programmer circuit I threw together a couple of years ago for another project that I resurrected for this one.
I'd tried several of the simple designs I'd come across on the web (TLVP, and a few others), and none had worked reliably so I rolled my own using some junk box parts, and it turned out pretty bulletproof. I can use a 20ft or more cable and it still works fine.
The component choices are rather ad-hoc, and could be dialed in better, but I figured if it ain't broke, why fix it? And hey, it's under 10 bucks.
Anyway, I thought I'd post it here so y'all can laugh at it, or try it, or whatever.
I've programmed 16F877a's and 18F2320's with it without issue. I'm guessing you could do ICSP stuff too, but I've never tried it.
Note that the optoisolator symbol has one led backwards but the pinout is correct, and the 74244 should be a 74LS244.
Otherwise it's accurate. I knocked it out in the GEDA suite when I went to copper after yanking it off a proto-board it lived on for a couple of years  :
It's Tait compatible so on XP IC-Prog 1.05D the tait setting works great. 1.06x for some reason (for me) does not. You'll need to set the parallel port to SPP in BIOS.

Thanks for a fabulous forum, guys.

 

[prschmitt]

Oh.. one more thing..
Power is a 12vac source.. like a wall-wart 

 

[gyraf]

Very cool device!

Jakob E.

 

[prschmitt]

Very cool device!

Jakob E.

Thanks for the compliment, Jakob!
Much appreciated coming from you!

I know most folks are into USB these days, and I'll be using a self-booting setup, but I have several 877a's hanging around, you have to get the boot code into the darn thing in the first place.

It's been a while, but I figured I'd use the hefty pulldown spec of the PC printer port and an optoisolator to go current mode to help reduce some of the ringing I was seeing on the data and clock lines (should have terminated to the positive rail, too, but it worked anyway) , but the big thing turned out to be terminating the shield at both ends.
Basic transmission line stuff, as I understand it.
Interstingly, just grounding directly at the pgmer end didn't work, but a cap did. 

 

[renx]

Welcome Prschmitt, and thanks for your post.

Nice to see someone is developing their own stuff instead of just copying other work and contributing minimally. Good work!
I have been working with PIC32 at work for the past two years and I noticed a couple of USB audio projects in Microchip's peripheral library. I bet they would be interesting to you.

Regards, Renx.