Edson Brusque wrote:

>   I've tried to make it with two PIC16F84.  One is for LCD display
> control who is receiving RS232 at 9600bps.

  I trust you refer to an LCD display module using a HD44780 controller
or similar?

> The other do all the remaining functions, scans the keypad, sends DMX
> and sends RS232 to the LCD controller.

  Noted: sends DMX.  Generally held to be far easier than receiving it!

>  This aproach worked ok, but I'm trying to make it with a PIC16F877
> (final unit would use a PIC16F873).

  This chip has a UART.  Should send DMX with considerable ease.  Need
to use suitable crystal of course.

> The problem is that I'm using the TIMER1 (16 bits) to send DMX at it's
> interrupt

  Why do you need this interrupt to send the DMX if you have the UART?

> and the TIMER0 (8 bits) to control the display at it's interrupt.

  Why do you need a timer to control the LCD?  Why interrupt?

> So, everytime the DMX packet is sent (aprox 4 times for each second),
> the display makes a little stop.

  How can the display "stop"?  I shouldn't have thought it was going
very far. :)  IOW, what does it need to update so rapidly that the
pause can be seen?

>  Someone have some tip on it's trick bag to help me? Or I have to give
> it up and return to use two PICs?

  Look, I'm not an expert but I would have thought this chip has a
hardware UART to do the DMX, so you use it for that function.  It would
appear to have more than enough pins to drive an LCD and keyboard as
well, and using the hardware UART, you should have no speed problems.

  In particular, using two PICs as it seems to me, would lead you to
waste inordinate resources (time, code space) simply communicating
between the two.  Lack of space for strings should be the major reason
you couldn't do it all in *one* 16F84, so am 877 or 873 should be a
piece of cake.

  And I doubt you'd have any need to use interrupts for this task; the
code should be quite able to perform a given step and poll the timer if
it needs to delay by a precise period to the next step.  LCD display
code could be interleaved into this and should thereby be self-
regulating.
--
  Cheers,
        Paul B.