I'm working on a design that will require two 8x2 character displays. Can I run them both in 4 bit mode, paralleling all but the 'E' pin? Software cold slece which 'E' pin to toggle, thus selecting which display to operate.
This would save a lot of i/o pins.
On a sunny day (Fri, 10 Sep 2010 06:43:03 -0700 (PDT)) it happened rangerssuck wrote in :
That should work, or you could each give them a PIC and use a soft out serial line to each, takes 2 pins total, very cheap PIC with internal osc, no external parts. Makes it easier to place the displays further away too.
Should be fine.
Some OLED/LCD controllers allow SPI mode. It might save some more pins than 4 bit mode.
So I thought - just wanted a second (and now a third) opinion.
I'm not quite that crunched for pins, and I want to stay with more 'standard' displays modules, at least until my customer makes up his mind about some things.
ssuck
Thanks, but I'm not quite *that* crunched for pins, and the displays aren't that far away, either. Besides, if I were to go this route, it would be a very cheap AVR...;-)
Take a look at the way logitech drives their G15 and G19 keyboard LCD displays.
Linux boys managed to hack it to. Some have even put video up on them.
Hell, two of those, and yer done!
Would please post your results, if you find this approach is successful? It would be useful information to tuck away in some back corner of the mind... just in case. :)
Thanks.
-mpm
Look at the larger LCD modules using the same Hitachi spec chip, they put two controller chips on the same board, guess which single signal line gets duplicated?
Grant.
Will do. I'm laying out a circuit board right now, pretending that it will work. It will probably be a couple of weeks before I fire it up, though - Lots of other circuitry to deal with.
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