Hello all:

I just recently built my own p16pro40 programmer. I had built it once last summer (and it worked then), but when I tried it again a couple of weeks ago, the thing had quit working.

I have rebuilt it multiple times. I can hook it up to my desktop computer and set the correct pins high/low using Winpicprog and Winpic. The correct LEDs light up, and I checked the voltages coming from the parallel port (3.35 volts high and .09 volts low). I also checked the voltage going to the PIC during programming; it is 12.82 volts. Is that high enough?

I have tried programming a couple of 16f628a's as well as a 16f877a. The programmer/software seems to read the PIC with no problem. When I try to write to it, though, it reads back a blank PIC. That's why I ask about the voltage being high enough, because I know that is one reason why it might not program correctly. I have tried all of the suggestions on other boards referring to the the p16pro40 (adding 10k resistor to the PGM port, removing the optional resistor and capacitor shown in the schematic, powering it using two 9V batteries instead of a wall wart, running the software in Windows 98 instead of XP).

Can anyone think of another reason why it might not be successfully writing to the PIC? Thanks a lot for your help.

 

Try increasing the programming delay time, also reduce Vpp Delay to 1 - if you've set the internal oscillator this will allow you to access programming mode before it starts running.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

You're quick Nigel. Thanks for the response. I tried increasing the Prog Delay as much as possible and lowering Vpp delay, but it is still not programming. The 877a does not have an internal oscillator either, so the Vpp delay should not be an issue (although I thought it might be an issue for the 628a).

By the way, I tried changing these values in both the 1.91 and 1.95e versions of WinPicProg.

I am also having a weird issue with the WinPicProg software. When I go to the hardware setup (in both versions), it allows me to set each pin to high or low by clicking on the buttons at the bottom. If I go to Programmer Type and click on P16PRO40-7406, though, I can no longer click on the buttons. The buttons are there, but they don't do anything when I click them.

In addition, in the beta version, there is a setting for MCLR whenever I open up the hardware setup (even though P16PRO40-7406 is already selected). If I click on the programmer type again, that column disappears, and I can no longer click the buttons to set the pins high or low. That is probably a bit confusing, so let me know if I can clarify more. See the screenshots that I have attached.

Thanks!

Attached Images

	before.JPG (39.1 KB, 5 views)
	after.JPG (36.1 KB, 3 views)

 

The buttons only work on the Custom setting, MCLR disappearing looks to be a bug!

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk