Clock based on a 16F628 pic

[Mr RB]

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I just used a spare 16F628 as among the 3 16F676's that I had up to yesterday, none were correctly recognized by the easypic4 dev board .
Today, I bought to other ones, and I'll try in the next days to program one of those.
...

With the EasyPIC4 and the 16F628 there is an "issue" with the LVP pin PORTB RB4. If this is allowed to float or go high you can't program it properly and the programmer will report an error. The EasyPIC4 PIC-FLash firmware seems to do a full erase on the 16F628 before it tries to program it, which resets the config fuses to the orig settings (LVP enabled).

What you need to do is move the PORTB pull-up jumper to the "pull-down" position. This holds RB4 low so the PIC will then program properly. This can be a bit of a pain but it will fix the issue.

I can't speak for the 16F676, but it is quite likely it is the same issue if "none were recognised". Otherwise make sure you put the PICs in the correct 18pin socket (as there are 2) and set the programming jumpers right (see the manual).

 

[ced]

Hi,
I almost sure to have mislead myself, putting sometimes while programming 16F628 pic in the wrong socket: dip18A instead of dip18B . Thanks for reminding me about the easypic4 setting rules before programming. For the 16F676, I forgot to adjust the JP3 and JP4 jumpers to select dip14 socket .
Besides, I have seen for sure that the breadboard has some problems.
Shifting the whole circuit a few rows up on the breadboard solved the problem with the 16F628, once programmed .