Re: [Gumstix-users] SPI reading and writing to register

[Scott E. <sc...@ju...>]

I'd probably start with spidev first. It's a generic spi driver built
into the stock Gumstix kernels. You can google it.

Gumstix brings out two CS pins for SPI Bus 1, but both are taken by
display drivers in the default kernels. Only one driver can claim a
SPI Bus CS line at a time. CS0 is taken by the 4.3" display driver and
CS1 is taken by the 3.5" display driver.

You'll need to disable one or both of those display drivers if you
want to use those CS pins.

This entails modifying the kernel config file (defconfig) and 
rebuilding it.

Make the following change to give spidev access to CS0

CONFIG_TOUCHSCREEN_ADS7846=m
to
# CONFIG_TOUCHSCREEN_ADS7846 is not set

Make the following change to give spidev access to CS1

CONFIG_PANEL_LGPHILIPS_LB035Q02=y
to
# CONFIG_PANEL_LGPHILIPS_LB035Q02 is not set

In the end spidev might not be fast enough for you depending
on how often you want to sample the accelerometer. But it's
an easy way to checkout your hardware and basic communication.

I'm working on some Overo SPI stuff today as well if you want
to ask some more specific question.

You can contact me off list.




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