[uClinux-dev] use RAM over SPI

[stefan.ulbrich at stud.uni-karlsruhe.de]

Hello list!

I want to create an embedded SBC capable of running ucLinux. I want to 
use an arm7tmdi with 12-Bit AD/DACs from Analog devices. The second 
requirement is the capability to drive a LCD screen.

As this arm7 mC has only 16 external adress lines I cannot adress 
enough memory to run linux nor a LCD controller. But this spring a new 
LCD controller from Epson is announced that can be adressed to via SPI 
and contains a SDRam controller. An External RAM therefore can be 
accessed through the SPI interface.

I'm a completely new to linux internals so my question is if it is 
generally possible to tell linux to use RAM over the SPI lines. Does 
there exist a RAM driver that can be altered (for example use the 
internal ram as a chache, etc.).  If so which book or resource is a 
good place to start reading?

thank you very much in advance,

cheers,
stef