PICall Programmer 12F675 Issue

[PeterK]

I recently programmed a 12F675 and after it was programmed and verified I could not have any access. (no read, erase etc)

Any suggestions?

Peter

 

[Exo]

Don't know about picall, but some programmers, like jdm, have problems with the 12f675 when running on internal oscillator. They turn VDD on before VPP and the pic starts running its program wich prevents it from gooing into programming mode, maybe the picall's problem is similar...

 

[Nigel Goodwin]

Don't know about picall, but some programmers, like jdm, have problems with the 12f675 when running on internal oscillator. They turn VDD on before VPP and the pic starts running its program wich prevents it from gooing into programming mode, maybe the picall's problem is similar...

Yes, I believe the programming spec for most PIC's is that Vpp has to appear no later than 250uS after Vdd, if the internal oscillator is in use. If there's no internal oscillator, or it's not enabled, it's not critical.

I found this with WinPicProg with the 16F628 and modified it accordingly, making the delay between Vdd and Vpp adjustable.

 

[PeterK]

PIC12F675

Thanks Nigel,

Used your programmer, everything OK

Peter