Re: [Gumstix-users] Help: i2c with console-vx

[Dave H. <dhy...@gm...>]

Hi shakka,

> I am using Verdex XM4 + console-vx (Rev1851) with OE.
> I would like to use i2c on console-vx to read/write a device. I am not sure what I need in order to make this happen.
> I have tried the following queries on the gumstix:
>
> root@gumstix-custom-verdex: /home/root> modprobe i2c_dev
> root@gumstix-custom-verdex: /home/root> modprobe i2c_pxa
> root@gumstix-custom-verdex: /home/root> grep i2c /etc/modules
> root@gumstix-custom-verdex: /home/root> lsmod | grep i2c
> i2c_dev                 5828  0
> i2c_pxa                 6912  0
> i2c_core               16816  3 i2c_dev,i2c_pxa,tsc2003
> root@gumstix-custom-verdex: /home/root>
>
> I have also saved i2cRead.c and i2cWrite.c from the gumstix i2c docwiki page and i2c-dev.h from lm_sensors.
>
> Some of the questions I have are:
> 1. How do I connect my device to console-vx. I see the SDA and SCL homes but where do I get ground?

The 8-pin connector that has SDA (on pin 2) and SCL (on pin 4) has
ground on pin 1 (I got this from looking at the schematics).

> 2. Do I need to install any pull-up resistors? if so where?

I think it depends on exactly which console-vx you have. The later LCD
ones already have pullups. What's the revision number of your board?
(a 4-digit number, probably one of 1401, 1638, 1753, 1833, 1851)

> 3. The modprobe command shown above did not return anything. Are the i2c modules properly loaded? do I need to do anything else?

That's normal (only the really old i2c modules printed something when
they're loaded).

> 4. Should I just compile i2cRead.c and run it on the gumstix? Is that all that I need to do?

Should be. You need to compile it using the same version of buildroot
or OE that's installed on your gumstix. There is a program called i2c
available as well. I think it's standard on the newer OE builds.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/