PIC and P16PRO programmer

[sandeepa]

Hello all

I have made the P16PRO programmer by Bojan Dobaj given on www.winpicprog.co.uk.On programming,I get the "Verify failed at 0000"error.I am using the Winpicprog software.

I have read almost all the stuff regarding this problem on the web.I am getting a stable 13V on the MCLR/vpp pin.I am supplying it through 2 9V batteries.I have rechecked the board several times,also got it checked from others,all seems to be fine.

I think the problem is that when I toggle the Output line(throught the hardware section provided in the software),the Input doesnt change when the PIC is inserted in the socket.Withut the PIC it changes all fine.
i.e.with a HIGH on the input of the buffer,74LS05,I get a low(0.15V) at its output.However with a LOW input,the output raises to only 0.66V.The same thing happens for the Clock line.However without the PIC inserted in teh sockets,I get the correct HIGHs and LOWs.
The supply in all cases is as required and nothing heats up or anything.
Also the Vpp40 and other signals change correctly when toggled.
I hope what I have said is clear.If not,I ll try rephrasing it.

What could be the problem?Could it be a bad batch of the PIcs?What else should I do/check/change?

Please help.
Thanks.

 

[Nigel Goodwin]

Hello all

I have made the P16PRO programmer by Bojan Dobaj given on www.winpicprog.co.uk.On programming,I get the "Verify failed at 0000"error.I am using the Winpicprog software.

I have read almost all the stuff regarding this problem on the web.I am getting a stable 13V on the MCLR/vpp pin.I am supplying it through 2 9V batteries.I have rechecked the board several times,also got it checked from others,all seems to be fine.

I think the problem is that when I toggle the Output line(throught the hardware section provided in the software),the Input doesnt change when the PIC is inserted in the socket.Withut the PIC it changes all fine.
i.e.with a HIGH on the input of the buffer,74LS05,I get a low(0.15V) at its output.However with a LOW input,the output raises to only 0.66V.The same thing happens for the Clock line.However without the PIC inserted in teh sockets,I get the correct HIGHs and LOWs.
The supply in all cases is as required and nothing heats up or anything.
Also the Vpp40 and other signals change correctly when toggled.
I hope what I have said is clear.If not,I ll try rephrasing it.

What could be the problem?Could it be a bad batch of the PIcs?What else should I do/check/change?

Please help.
Thanks.

Are you absolutely sure you're connecting the PIC the correct way round?, and that it's positioned correctly (assuming a 40 pin ZIF socket).

Also, make sure you have the correct 5V on the Vdd pin(s) of the PIC, if not the I/O pins will feed through their protection diodes and try and feed the circuit (which would pull the pins down).

 

[martinH]

What device are you trying to program..
I had this same error when i inadvertantly picked up a 16F876A
instead of a non A type,not realiseing at the time hese use different programming techniques.

 

[sandeepa]

The Vdd does not rise upto 5V when the PIC is inserted.Its only 2.5V or so.Without the PIC,its a stable 5V.The transistor also heats up when the Vdd is switched ON.
Tried programming another piece(PIC16F877A),this one programmed sucessfully.However on this one,there is a voltage of around 2.5V even when the Vdd is OFF.Is this correct?
Thanks.

 

[Nigel Goodwin]

The Vdd does not rise upto 5V when the PIC is inserted.Its only 2.5V or so.Without the PIC,its a stable 5V.The transistor also heats up when the Vdd is switched ON.
Tried programming another piece(PIC16F877A),this one programmed sucessfully.However on this one,there is a voltage of around 2.5V even when the Vdd is OFF.Is this correct?
Thanks.

As I mentioned previously, if the I/O pins are high, the voltage on the I/O pin will feed through the protection diodes to the Vdd pin.