Hi all,
firstly I would like to thank those on the list that have provided =
feedback and assitance to me on my recent postings.

I am (hopefully) getting close to the end of my first PIC project! I =
have a couple of questions regarding hardware and software design. My =
project consists of a bit banged serial port, timer, encoder counter, =
and psuedo PWM to drive two modified hobby servos. This is all done on a =
16F84.

From reading this list I understand it is good practice to keep =
interrupt service routines short, and use flags which are polled in the =
main loop. I am thinking about using this method for the timer, and the =
serial port. The code would look something like:

main()
{
    while (1)
    {
    if (timer_flag)
        do something
    }
}

interrupt void isr()
{
    if interrupt cause by timer
        set timer_flag =3D 1;
}

and the same for the serial i/o...  is this good coding style for PIC's?

Secondly, if this is the solution I end up using then I am probably =
going to want to tie at least three incoming lines to the RB0/INT pin =
(two encoders and the Rx line for the serial port). How would I =
multiplex (is that the right word??) these lines togeather? What =
component(s) would I use to do this?

I am thinking that every time an interrupt occured on RB0 I could just =
check the values of the other i/o pins to see what caused the interrupt.

Sorry for the long winded e-mail, turns out this project was a little =
more involved than I first thought it would be ;-)

Thanks very much for any advice,
kind regards,
James Fitzsimons

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