PIC programming question

[Andy_123]

Hello,

This question probably asked here many times:
P16Pro40 programmer:
works just fine with 16F628 and 12F675
Can't get it to work with 16F870 (tested 2 different chips)

Voltage 12.95V, no spikes.

Checked with 2 different software packages.

Any ideas?

Also, can a low voltage programming mode be used for 16F870 with P16PR40?

Thanks
Andy

 

[Nigel Goodwin]

Hello,

This question probably asked here many times:
P16Pro40 programmer:
works just fine with 16F628 and 12F675
Can't get it to work with 16F870 (tested 2 different chips)

The 16F870 probably requires Vpp40 rather than Vpp on the P16PRO40, have you programmed other large chips with it?.

 

[Andy_123]

Thanks for reply.

No I did not program any large chips, I have now only few 16F870 chips, rest of them small.

Yes it does require Vpp40 and I see different LED coming up and I see 12.95V on pin 1.
I checked spec on 16F87x and programming voltage is 13+/- .5V
It is little higer than voltage spec for 16F628 and 12F675 (12-13V)

Should I try to bump Vpp40 voltage to 13.5 or it may damage rest of chips?
Also I will try to replace transistor on Vpp40 line.

 

[Nigel Goodwin]

Thanks for reply.

No I did not program any large chips, I have now only few 16F870 chips, rest of them small.

Yes it does require Vpp40 and I see different LED coming up and I see 12.95V on pin 1.
I checked spec on 16F87x and programming voltage is 13+/- .5V
It is little higer than voltage spec for 16F628 and 12F675 (12-13V)

Should I try to bump Vpp40 voltage to 13.5 or it may damage rest of chips?
Also I will try to replace transistor on Vpp40 line.

13.5V shouldn't cause any problems, but I've never had any problems with P16PRO40's like this. I've never had a 16F870 to try, but I've used 16F876 and 16F877 without any problems.

Did you build the programmer from a kit (with a PCB) or did you build it from scratch yourself?.

 

[Andy_123]

I built programmer using schematics and board from your site.


I am designing and building electronic devices for over 30 years, but this is my first project with PICs

I will try to replace transistor and bump the voltage to see if it helps.