The current display shields are somewhat limited in that you can have an HDMI display OR an LCD display…and that’s it. Only a single monitor.
I ran across a driver to run some small LCD displays via SPI or GPIO[or 2 SPI at the same time, or SPI and GPIO…etc] on the Raspberry Pi:
https://github.com/notro/fbtft
Checking through the driver code, the only thing that is specific to the Raspberry Pi is the pin assignments - and even there the driver is extremely flexible and allows you to specify the pin assignments when loading the driver, so it should be usable right out of the box without any changes.
I went ahead and ordered a couple inexpensive LCD’s from Sainsmart[one ‘ardunio’ module and one SPI model] which are already supported by the driver so as soon as I get them in I can give it a try.
Frames per second will of course be rather low when using GPIO, but for a text console or a small desktop that shouldn’t matter much.
I was wondering if anyone else has used GPIO or SPI and if so, what drivers your using? The main downside of FBFT is that since the Pi doesn’t support the device tree yet, all those device settings either have to be coded in the C program or inserted via command line - but it doesn’t seem too difficult to move those configurations to a DTS file later after confirming the driver works to begin with.