in-circuit serial programming in pic16f877?

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asic1984

Joined: 15 Nov 2003
Posts: 266
Helped: 3

07 Feb 2005 17:04 pic16f877 incircuit

hi

how can i use the in-circuit serial programming of pic16f877 in making programmer

is it the same method used with the jdm programmer

thanks for help

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VVV

Joined: 26 Nov 2004
Posts: 1584
Helped: 290

08 Feb 2005 18:25 pic16f877 vpp circuit

To program the PIC16F877 you need four signals, plus ground. The signals are: Vdd, Vpp, RB6/PGC, RB7/PGD.

Since these have to be available to the programmer, you can use a 10-pin header (2x5 contacts). These 4 pins on the PIC are directly connected to 4 pins on the header. The corresponding pins on the other row of the header are connected to the normal point in your circuit. You install 4 jumper links for normal operation. When you need to program the PI, remove the jumper links.
Your programming adaptor should apply the programming signals only to those 4 pins on the header which are connected to the PIC, plus GND, which can be the last two pins on the header.

Sometimes you can use resistors in series with RB6, RB7 (1-10k) and use only two jumpers, for Vdd and Vpp. Of course, RB6, RB7 still have to be connected to the programming header. If you cannot use these resistors for some reason, use 4 jumper links.

Hope this helps.