2 Pics - 1 LCD

[hunt4it44]

does anyone have any suggestions how I can interface 2 pic's to one lcd. Through software, i can make it where only one pic will try to communicate with the LCD at a time. However, when i wire both pics to the LCD, neither pic is able to communicate. Can i simply use an OR gate? perhaps a 3rd pic configured to act like an OR gate?

all suggestions welcome.

Thanks

 

[JD1]

Use a Mux Unit, .............

JD

 

[3v0]

Having more then one uC talk to a single LCD is difficult.

Better to have one PIC control the LCD. Have the 2nd, (3rd..) PIC send the info to be displayed to the first who then displays the needed info.

How you do the communication is up to you. Lots of options.

The same question was asked here not too long ago. Search for it if you want to read the entire thread.

does anyone have any suggestions how I can interface 2 pic's to one lcd. Through software, i can make it where only one pic will try to communicate with the LCD at a time. However, when i wire both pics to the LCD, neither pic is able to communicate. Can i simply use an OR gate? perhaps a 3rd pic configured to act like an OR gate?

all suggestions welcome.

Thanks

 

[hunt4it44]

thanks

thanks for the response. i guess i need to see what i can do about passing data from one pic to the other which will control the lcd.

 

[Nigel Goodwin]

You just need a single pin on each, and send serial data - you can even buy serial LCD modules, these just have an on-board PIC doing the processing.

 

[Wingmax]

How about using 2 PIC in master slave configuration. the master connect direct to the LCD. The slave can pass on message in 4 bit mode to the master and the master then display to the LCD.

 

[mcs51mc]

Too bad we don't know what controller is on the LCD.
If it's the well known D) Hitachi HD44780.
Then you could buy a 4 lines * 40 characters LCD.
It has 2 controllers on it one for the first two lines and the other for the last two lines.
Such LCD has 2 enable lines (one for each PIC) and multiplexed datalines (to both PIC's).