Labx2 icp problem .. help please

[DavidFMarks]

I have built a pcb to opreate an led matrix (Christmas star ! ) Works ok but i want to reprogran in circuit via an epic programmer. The initial experiment used the lab2x board which worked a treat. This board developed and intermittent fault and has since apparently died. My new pcb includes the circuit used on the lab2x but attempts to program via that header result in the dreaded program error message. I feel sure that during all the rather unenlightened changing of configuration settings etc when lab2x packed up I have done something stupid (again!) Any help would be appreciated.

[mister_e]

May sounds silly but, did you program the bootloader firmware in your new PIC first?

If so, most of the time, default config fuses are great... unless your device programmer is not set to program them.. yeah it happen.

[DavidFMarks]

Not so silly actually as I didn't - Reason being that I'm pretty certain that the chip which i did get to program before the labx2 board went kaput didn't have a bootloader on board ..,or is that impossible. Presumably I have to download said boot loader from somewhere ! Thanks for you patience !

[DavidFMarks]

Sorry to be a pain but I have been doing some more reading up on this and it appearsfrom the notes on the melabs site that by connecting the epic programmer direct to the labx2 board via the 10 pin headers it is possible simply to program direct from the epic with no special software and this is what seemed to be working before the board developed a fault I have replicated this circuit on my new board. The only things I have not done are to pull rb3 low or connect a bypass capacitor to Vdd. All I get when trying to program is a program code error. Can't check again at the moment as I have blown up the 16f877 by plugging it into the board wrong (to avoid which was the reason I wanted to use icp in the first place. I ordered some new ones from my uk supplier who told me that the 16f877A was the same as the 16f877. Turns out that it isn't and my epic programmer will not program them .. i am none too pleased !)

[mister_e]

Yup the PGM pin have to be laded to gnd, with resistor <10K it's safe.

Have a look over there
http://www.melabs.com/support/icsp.htm

Make sure all VDD and VSS are connected too. The capacitor is a real must as well, unless you'll run into problem soon or later.

[DavidFMarks]

Many thanks, will try that when the new chips arrive
Cheers David M