pic16f88 programing problem

[sandeepa]

Trying to program PIC16F88 using P16pro40 and the winpicprog software.
Config settings are internal oscillator and MCLR pin is used for I/O.LV programming disabled, code protect off.
I get a config fuses verify error for these settings.
If, i change the oscillator to XT or HS, the pic programs fine.

I tried changing the time settings in the hardware option.That didnt help.(Changing these settings gave verufy errors even in XT and HS oscillator settings)

What could be the problem ?

Thanks.

 

[Nigel Goodwin]

Does the chip program OK?, and what do the config fuses read when you read the chip back?.

 

[sandeepa]

When the oscillator settings are set to internal, which is what i want, i get the config fuses error.When read back, the fuses read back as something random.Its not the same everytime.
Also, when I erase and then read back, it reads back as something random-the program memory, eeprom as well as the fuses.

However, all is fine when the oscillator is selected to HS or XT- verify successful, reads back correctly and erases correctly as well.

 

[Nigel Goodwin]

If it's only when you set the internal oscillator, it might be that it's starting to run before you can get to programming mode - try setting the Vpp delay to the minimum.

 

[sandeepa]

Thanks !
I changed the Vpp delay to 0.Prog delay is 10.
Verified successfully this time.