[Gumstix-users] noob question

[David B. <dbe...@gm...>]

So if I understand correctly, I could hook up a shift register like
this: clock -- GPIO 1, data-in -- GPIO 2.

I could then push a '1' into the register by writing 'set' to GPIO 2
and then writing 'clear', 'set', 'clear' to GPIO 1. Right?

I understand this is much slower then writing a kernel mode driver
that accesses the gumstix's registers directly, but how slow would it
be?
Would writing one bit this way take more than 10 milliseconds?
I need to write 32 bits in 1/2 a second or less.

Any tutorials that anyone has on using the I2C bus from a user mode program=
?


--David