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[on:]

I am looking to make a small slot machine with 3 small lcd's for the 'reels'
I am looking at using these for the first build:
http://www.adafruit.com/products/338

My question is this... Is it possible to run 3 lcd's on the Uno (i swear i googled for hours yesterday and could find very few projects with more than one LCD), and if NOT, is there a board this would be possible on, or do i just need a dedicated graphics board for each lcd?

The graphics would be very simple shapes, set to 'spin' like a real slot machine.

This is my first real arduino project, and if I can get pushed the right direction I will name my 2nd born child after you..
Thanks in advance.

[Reply #1 on:]

You can get 3 LCDs to run on an uno if you want (its easier on a mega though) if you have some fun with shift registers. There's a LCD from shiftreg library on the arduino playground thats pretty easy to work with, heres the link.
https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads
However that library I've only made work with the sparkfun/adafruit 2x16 character, and 4x20 character displays. Haven't tried anything with any other screens yet.

However after reading the info about the screen it says you need 3-5 output pins to drive it (something about whether or not you want to run the chip select and reset pins) so if you could set it up right you could probably get by with the 3 screens straight into the uno, but you'd be tight on space for other stuff.

[Reply #2 on:]

YOu can also use 3 serial LCD's , easier and maybe less fun, but with NewSoftSerial a piece of cake...

[Reply #3 on:]

The Nokia displays are already "serial" in the sense that they use SPI. This also means that you can use the built-in SPI library. Tie the "chip select" of each display to a different digital pin, but have them share SCK, MOSI and MISO. When you want to talk to a particular display, activate its chip select pin, and use MOSI to tell it what to do.

[Reply #4 on:]

The Nokia displays are already "serial" in the sense that they use SPI. This also means that you can use the built-in SPI library. Tie the "chip select" of each display to a different digital pin, but have them share SCK, MOSI and MISO. When you want to talk to a particular display, activate its chip select pin, and use MOSI to tell it what to do.

Yeah that's the gist of it, but the PCD8544 library appears to store a buffer for what's displayed on the LCD so if you had only one instance initialized all three screens would share that buffer.

It looks like the straightforward method would be something like:

Code:

// pin 7 - Serial clock out (SCLK)
// pin 6 - Serial data out (DIN)
// pin 5 - Data/Command select (D/C)
// pin 4, 8, or 9 - LCD chip select (CS)
// pin 3 - LCD reset (RST)
PCD8544 nokia1 = PCD8544(7, 6, 5, 4, 3);
PCD8544 nokia2 = PCD8544(7, 6, 5, 8, 3);
PCD8544 nokia3 = PCD8544(7, 6, 5, 9, 3);

...then normal stuff.