Geode integrated peripherals support?
bsd at dino.sk
Thu Jan 20 21:52:56 PST 2005
On Friday 21 January 2005 00:51, John-Mark Gurney wrote:
> Milan Obuch wrote this message on Wed, Jan 19, 2005 at 10:00 +0100:
> > Great, could we cooperate?
> Sure, though Joerg Wunsch has been doing work w/ I2C more recently than
> me, so you might want to drop him an email.
Is he on this list? I have no other idea how coould I reach him.
> > I know there are two modes - bit banging software i2c bus and real
> > hardware controller. Which one would be easier to begin with? With geode,
> > both are possible. Pins designed for ACCESS.bus (at least the second,
> > there are two buses integrated) can be used as GPIO pins.
> The hardware I worked on was bit banging only, so I used that interface
> and it was surprisingly easy, since you just define an interface that
> will get called by the i2c bus to do the necessary toggling... Of course
> this is more cpu intensive since it requires timing and other things
> like that..
Maybe I will try to make bit banged version first. Just when I find all the
subtle details necessary to toggle pins...
> Take a look at sys/dev/iicbus/iic*_if.m. Those are the two different
> programming interfaces. You of course just need to do one of the two...
I did. Actually first I must figure how this all contributes to total
picture... I am on my way. I must first know the hardware part, which is not
that easy on the first stage, but I am reading through specs, some examples,
mostly in assembly. I am doing my homework :)
> You can take a look at lpbb for a simple example of the bit banging
> interface... sys/dev/ppbus/lpbb.c The other controllers also implement
> iicbus directly.. You can look at the modules/i2c/contollers/*/Makefile
> to see who uses iicbus_if.h to see examples that implement it..
On the other side - what is sys/dev/pcf directory for? I do not see those
files referenced elsewhere... Other than that, device pcf looks like the best
candidate to work with. I would like to use integrated controller, naturally.
N. B. No need to send cc: to me, I am subscribed.
More information about the freebsd-hackers