> 1. When using LVP the programmer provides DATA (PGD)  and CLOCK (PGC)
> signals and few others.
>      I like to know if the PGC is only for the serial data processing
> or it drives ALL the
>      PIC internal hardware modules (including the programme/data memory
> clock)  that takes part at the programing process.

PICs that have only an external clock option (xtal, extclck, etc) can be=20
programmed without such components in place, so I guess the PGC *must*=20
be the clock for everything, because at that moment there is no other clock=
..

OTOH, some PICs have "internally timed" operations (write, erase), that=20
time themselves without the help of the PGC. Hence there must be some=20
notion of time within the chip, but that does not imply a clock (it=20
could be an RC one-shot).

> 2. In case i have a PIC that operates with external clock , and i need
> preform "in circuit programing" of it,
>      does the total process time is limited only by the
> PGC+"Programming process design limitation"  or it got also
>      some dependency at external clock.

The external clock is not mentioned in the specs, it doesn't even need=20
to be present. Also: while you are programming the chip, the=20
configuration fuses are done last. So most of the time the clock fuses=20
bits are not set yet. So how could the chip know which clock setting to use=
?

--=20

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu
C++ on uC blog: http://www.voti.nl/erblog

--=20
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