how? 2 wire lcd with pbp?

[sougata]

Hi,

This is a serial LCD using a PIC. It takes commands in the LCDOUT style, hence is easy to incorporate.

Regards

Sougata

[Demon]

One note to those having problems with these I/O expanders, remember to scroll all the way down the PDF and check out the timing requirements.

MCP23008: top of page 23.

Robert

[Demon]

Sougata,

I checked your attachment and I noticed something odd. The LCD is parallel, it's the communication to the PIC that is serial.

Or am I more confused than I think I am?

Robert

[sougata]

Hi there,

Parallel LCDs are easily available and cheaper (at least here in India). The SELD is a dedicated PIC programmed with PBP that drives a normal parallel LCD. The PIC takes its command via a serial input thus freeing up resources on the main controller.

I personally use a PIC18F452 based circuit that uses interrupt based serial routine handling and gives me the freedom to use buttons and indicators at the same time. A complete user interface module you can say. This reduces wiring in my panel from the main coontroller and leaves the controller more useful for other sensing and control tasks.

Regards

Sougata