problem programming PIC 16F877A using Ponyprog

[viostan]

ponyprog write failed

Hi,
I am new on the forum.
I have a small problem programming a PIC 16F877A. I built myself a ponyprog serial programmer for PIC MCUs and i2C memories. It reads the pic ok, but i cannot write on it. I can write one byte anywhere on the chip, but if i try to write more than one i get a Write failed message. I can read it so the board must be good. (i verified it hundreds of times). For i2C memories it is ok
Can you please advise me? What could go wrong?
Thank you very much!

 

[pasicr]

ponyprog

Do you use external or internal power?
regards

 

[tijoseymathew]

16f877a vpp

the vpp part must be having some problem. This is when the pic can be written to but cannot be read. Try a hardware test by keeping vpp on and then check with multimeter on mclr pin.

 

[viostan]

ponyprog board

Hi, i am using 18V stabilized external power supply. The voltage on mclr is exactly 12.81V and stays like that all the process (read or write). it goes to 0 after the read operation

best regards!

 

[pasicr]

ponyprog pic16

Hi Viostan,
attach please your sch,
regards

 

[tijoseymathew]

pic mit ponyprog

are u connecting vdd to the mclr pin ???? This is required for normal operation but not for programming chk it also..

 

[viostan]

ponyprog programmer

Hi,
i have attached the schematics of the board, and it's PCB layout. it is only one board, all on it.
At this moment are missing from the board the folowing components:
R16, C2, C23. I just thought i should try without them. No result. Jumper JP3 is not connected (left as is).
The serial memory part of the board is therefore inexistent. When i use it i take transistor Q6 out and unconnect net6 from RB7 pins
(i did not forseen jumpers for those, unfortunately).
At this moment Q6 is present on the board and is working.
Nontheless, it should be working.

all the best!

 

[ragh1981]

Re: ponyprog programmer

Hi, Viostan,

Did the problem get solved, what was the solution for programming the PIC16F877A using Ponyprog2000?

regards
raghavendra

 

[viostan]

Re: ponyprog programmer

Hi Raghavendra,

I stopped trying. Built myself another programmer, different schematic, with a MAX232 (the best way to comunicate thorough serial port i think) which works fine everytime.

Regards,