interfacing a 4x40 LCD with the stamp
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roscopsk wrote:
> ..I have a 4x40 LCD which I'd like to use with my Stamp (BS2). As
> I recall, It's set up as 2 2x40 LCDs, with a separate controller
> and enable line for the top and bottom halves....Or, I was
> wondering how hard it might be to drive the LCD directly from the
> stamp. It won't need to do too much else...
Rory-
In all likelihood, the two LCD controllers can share five I/O pins
(R/S and four data lines) and use separate EN I/O pins for a total
of seven I/O pins for both, leaving nine I/O pins for other uses.
The code to drive a single controller is not that hard and examples
are readily available. Adding the dual controller capability would
simply be a matter of selecting which EN to activate. Shouldn't tie
up more than ~5% of your available code space.
Sure seems worth a shot before you shell out the bucks for a couple
of controllers.
Regards,
Steve
> ..I have a 4x40 LCD which I'd like to use with my Stamp (BS2). As
> I recall, It's set up as 2 2x40 LCDs, with a separate controller
> and enable line for the top and bottom halves....Or, I was
> wondering how hard it might be to drive the LCD directly from the
> stamp. It won't need to do too much else...
Rory-
In all likelihood, the two LCD controllers can share five I/O pins
(R/S and four data lines) and use separate EN I/O pins for a total
of seven I/O pins for both, leaving nine I/O pins for other uses.
The code to drive a single controller is not that hard and examples
are readily available. Adding the dual controller capability would
simply be a matter of selecting which EN to activate. Shouldn't tie
up more than ~5% of your available code space.
Sure seems worth a shot before you shell out the bucks for a couple
of controllers.
Regards,
Steve
Comments
I have a 4x40 LCD which I'd like to use with my Stamp (BS2). As I
recall, It's set up as 2 2x40 LCDs, with a separate controller and
enable line for the top and bottom halves.
I'm assuming that the simplest solution would be to just get two
serial LCD controllers, and then have them share the data lines.
Should they play nicely and get along with each other?
Or, I was wondering how hard it might be to drive the LCD directly
from the stamp. It won't need to do too much else, so I'm not too
worried about processor usage, but starting from scratch seems a
little intimidating...
Thanks!
Rory
What you could do is get one controller chip to control all of the data
lines and use some gate logic to switch between the two enable lines. I
believe it would take 3 stamp pins to do this. One for a serial LCD
control chip like the EDE702 and two pins to select between the enable lines.
Brian