I just assembled a P16PRO40 programmer from Amazon electronics, and I am having trouble programming a PIC 16F628. I have never successfully used this programmer before, this being my first PIC project. I am supplying it with 17 vac from an unregulated wall wart. I am using WinPicProg, with the settings for a P16PRO40 - 7407. I get the error message " Verify failed at Program address 0x000, Programming Aborted." I have already checked VPP, and it reads as 13.1 vdc. I am new to this, and not sure what to check now. Any ideas?

 

If you're using an unregulated wallwart, it's quite likely that it has excessive amounts of ripple on the Vpp line - this prevents the PIC entering programming mode.

Try powering it from two 9V batteries in series, I've run P16PRO40's like this for years!.

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

 

on the same two batteries :shock:

 

he has rechargable ones

okay bencanon does this problem come with only 18-pin devices? have you tried programming a 40-pin device? and does your programmer have a 7407 or a 7406?

 

No! - but I work at a place that sells batteries :lol:

They last a considerable time, as long as you unplug them when not actually programming - as the batteries start to go flat, you get the same verification error - as the PIC can't be switched to programming mode.

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

 

lolz thats nice !!!!

i would love to work at a place where i could get free batteries.

 

I tried with 2 9V batteries for the power supply, and got the same error. As for the Vregs on the programmer, I have a 78L08 and a 78L05. These were the two that I received the kit with.

I also used a borrowed JDM programmer with the same PIC, and got an error stating "Verify failed at address 0000h!" Should I try another PIC, or keep troubleshooting the programmer?

 

the PIC being bad could be a possibility. did you check the transistors before soldering them? and is the buffer IC working alright?

 

Update: I have tried it with another PIC 16F628, with the same results. I also noticed that the voltage regulators are getting rather warm when I have it plugged in for >a minute or so.
I also tried to program a 16F877, but the software no longer sees the programmer. The green LED no longer lights up when the programmer is connected and has power, the Vpp40 light is the only one on.
I did not check the transistors, and I do not know how to check the buffer chip, which is a 74LS05 on this board.


I am thoroughly confused, any help would be appreciated.

EDIT: I managed to get the PC to "see" the programmer again, and it acts normally, with the green power light coming on as intended, but the error is still present with 16F877 and 12C509A chips.

 

de-solder the BC557s and check them with a transistor checker. maybe, one of them might have been damaged.

tell me when you are done with the testing

 

2 have HFE readings of ~400, the other has a reading of ~350.

 

so the transistors are alright.

okay this is going to be time consuming but you have to give this a try. you have to verify the hardware functionality of each part of the programmer. take out the parallel cable out of the computer port. now start giving logic levels to the different pins on the connector and verify the logic levels created at the ZIF socket on the programmer by a logic probe (ofcourse there shouldnt be a PIC in the socket while you are doing this)

understanding the programmer is really simple. first there are buffers then there are PNP transistors. when the input to the buffers is a LOW, the base of the transistors is LOW, which means that the collector voltage is about 13 volts. if you have inverting buffers then the case would be the opposite. three of the inputs have such connections and the rest have just buffers and no driving transistors.

with your knowledge of electronics troubleshooting you can verify the functionality of the whole programmer. i think there is no other choice but to do this. only then you can trace out where the problem is. it may be the cable, it may be the resistors.

 

did you measure outputs of the voltage regulators? are you sure they are connected correcly?

 

I think you should be using the seting P16PRO40 - 7406 if you are using 74ls05 as the buffer.

 

I also having this problem last night when I opened my long abandoned (over 1 year!!) electronic kits drawer and picked out the writer for a new project. My programmer and software is exactly same as yours. The mpu I am working on is 16F876 (28pin PDIP). It "looks ok" on reading/erasing but does not work on writing. And at last I picked out a sand paper and file the pins of the mpu one-by-one. Now works like a charm!!

So I will suggest 2 things:
0. Check the 7406/7407 printing on one of the IC on the writer and has it set properly in Winpicprog.
1. If you are using ZIF socket (like mine), make sure the pin insertion is correct. You can tell by the middle LED on p16pro40 lighting up when really it trying to read. My 40-pin ZIF socket, unexpectedly, is found to have 41 rows......
2. If (1) looks good, pick out a piece of sand paper and try filing away the rust on the mpu tiny pins on all directions.

Hope it helps~