Using common alphanumeric LCDs (Hitachi 44780 controller or compatible), you
can attach as many as you want in a "bus" architecture.
- Use 4 lines for data I/O (DB0-DB3) tied to all LCDs
- Use 2 lines for control (RS and R/W)also tied to all LCDs
- Use 1 line for chip Enable (E), but this has to be a separate line for
each LCD
This is a total of 6 common lines plus one for each LCD.
Then you program the LCD in the usual way, but just enable one at a time.

Hope this helps.

Regards,
Andres Tarzia
Technology Consultant, SMART S.A.
e-mail: atarzia@smart.com.ar

-----Original Message-----
From: John De Villiers [mailto:jd62@PIXIE.CO.ZA]
Sent: Tuesday, October 26, 1999 16:36
To: PICLIST@MITVMA.MIT.EDU
Subject: Multiple LCD displays


Folks, i need info.

I have a circuit that i initially designed for a MAX7219 ( 2 of them )
display driver. I was using all 16 segments that the two chips could drive.
This sucks a lot of mA's, more than i can spare, so the obvious answer is to
use LCD displays.

Problem - i have 3 seperate displays ( one large 5 digit, one large 3 digit,
and one small 5 digit). With the MAX chips this all still only took up 3 I/O
lines. Are there any LCD display Kits/drivers that will allow me to cascade
3 seperate LCD displays.

Alternatively, i need suggestions on driving all these displays 9 like maybe
a separate PIC that handles just the displays and uses an I2C interface to
the main PIC. I've never used i2c before. Busy scanning the Mchip cd right
now for info on that.

John