2 PIC18F4520 for 1 LCD

[faridh3]

Hello,
Can we use 2 PIC18F4520 for 1 LCD16x2 ?
Thanks

[PCM programmer]

Possibly, if you can guarantee that one of the PICs is active and the other
PIC has its LCD connection pins set to "floating" (ie., set as inputs).
But, how are you going to guarantee this condition (only one PIC is active
and the other "disconnected", in effect) ? Holding the \MCLR pin at a low
level will keep the PIC in reset (assuming you don't have the NOMCLR
fuse selected). When a PIC is held in reset, all of its i/o pins are in a
"Hi-Z" (floating) state and are not active.

In general, avoid having two PICs connected to one LCD. Find some
other way to solve the problem.

[Mike Walne]

You could guarantee isolation with a hardware mux.

I did something similar (and the other way round) a long time ago when I wanted four hardware UARTS using MAX232s.

OR

Use PIC_1 to drive the LCD, PIC_2 simply tells PIC_1 what to display.

Mike

[faridh3]

okey thank you
the problem is, that i need to run 2 infinite loops at the same time and i have no idea how to do it.

[temtronic]

A third method is to have the LCD connected to one PIC(host/master), the other PIC is then a 'remote' or 'slave' and sends data to the 'host' or 'master' PIC which then displays that data on the LCD.

However from your last post it sounds like you really want to

start
do something, display result
do something else, display that result
loop to start

If you give an better description of the project, we can guide you to examples of code, either in this forum or the code library.

hth
jay

[Mike Walne]

Are you prepared to use more hardware?
OR
Do you want a purely software solution?

We need to know where to start from.

Mike

[PCM programmer]