Hello!
I have a question about in-circuit serial programming of the PIC16F877. What I would like to know is if all I/O pins are in the high-impedance state during programming ( except for the programming pins )?
what's the value of R in 16F877 board/MCLR circuit (low voltage hardware.pdf / p.1) ? can't read it on the pdf :evil:
this is certainly a critical value, as the Vpp generator has 1K on TL497 output