12F675 won't reprogram or erase

[mister_e]

probably but as i've tons of design who use internal OSC and MCLR as i/o, i'll probably mostely bet on the CodeProtect stuff. Sure you can reprogram but can't read back. This is probably why you got this error.

ALSO, you may look at the programming sequence and idle state. Some design may ruine your life when using ICSP. Same thing for some device programmer... like PICSTART wich is still great but sometimes a pain in ICSP.

How about doing another test... remove any load on ICSPdata, ICSPClk, and place a 10K pull-up + diode on MCLR pin like...http://www.melabs.com/support/icsp.htm


Then now, remove your code protection (CP and CPD), program ir, erease it. Once done, place your load on ICSPdata, ICSPclk and redo the same... about now??? If problem persist, how about if you shut down the unit, connect it to your programmer, the power-up the unit?

Now do the same thing with the MCLR. About now?

Set your code protect.... aboout now?