how to connect 4 PIC with 1 LCD?

[meera83]

i m using PIC16F877..
i would like to use 25 analog device as input signal, so i choose to use four PIC to control it(one PIC can control 8 analog input)..

the four PIC will send a command to LCD when either one of the analog device give input value..

the problem is how should i do in order to let four PIC share using one LCD?

if i use PORT C as LCD pin, then how the hardware circuit should i built to let four PIC send signal to PORTC?

thanks..

 

[Maxchang]

One way:
i think you can use one single PIC to contral the LCD.
it means that you should use 5 PIC.
Use 485 or can bus conmunicate with others.

 

[danciurea]

The easyest way to control the LCD is to have a small pic as a "LCD driver" and also act as some kind of master wich should be able to interogate the other pics via spi or other kind of bus for the measured values. But this aproach has the disadvantage of having a complicated hardware.

Another aproach is to have a single pic which will do all the operations (control the LCD and do the analog stuff).

If your analog readings are not so critical you can use an analog multiplexer to swich the inputs to the analog channels of one pic.


hope this helps

Daniel