atom feed10 messages in com.googlegroups.beagleboard[beagleboard] Re: i2c works?
FromSent OnAttachments
Bill GatliffNov 18, 2008 6:54 am 
ftag...@gmail.comNov 19, 2008 7:13 am 
Frank AgiusNov 19, 2008 10:39 am 
Jack PeacockNov 19, 2008 3:57 pm 
ftag...@gmail.comNov 20, 2008 3:48 am 
James Chen ???Nov 20, 2008 4:03 am 
ftag...@gmail.comNov 20, 2008 8:00 am 
John StowersNov 23, 2008 4:41 am 
ftag...@gmail.comNov 23, 2008 4:43 pm 
John StowersNov 24, 2008 6:48 am 
Subject:[beagleboard] Re: i2c works?
From:ftag...@gmail.com (ftag@gmail.com)
Date:Nov 19, 2008 7:13:33 am
List:com.googlegroups.beagleboard

I've been struggling to get i2c working on the Beagleboard, but I've recently (about 5 minutes ago) gotten it to work. I have successfully connected from the Beagleboard i2c-2 to a Gumstix Robostix i2c. I'm using kernel version 2.6.26-r64, with config options CONFIG_I2C_OMAP and CONFIG_I2C2_OMAP_BEAGLE turned on. To do the level shifting from the Beagleboards 1.8v to the Robostix 5.0v, I used a small board that uses the NXP PCA9306 level translator. On the Beagleboard I connected to the 2nd i2c bus on the expansion connector (pin 23 for sda, pin 24 for scl, pin 1 for 1.8 volts, pin 27 for ground) and on the Robostix board I connected to the i2c bus on the UART connector (pin 12 for sda, pin 16 for scl, pin 14 for 5 volts and pin 10 for ground). Most (all) of my problems were self inflicted, like connecting to the wrong pins on both the Beagleboard and the Robostix board.

I used i2cdetect (from i2c-tools-3.0.1-r0) on the Beagleboard to probe the address bus and the Robostix correctly identified itself as 0xb:

root@beagleboard:~# i2cdetect -ya 2 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- 0b -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- --

I then used a program called i2c-io (from the Gumstix/Robostix utilities) to read a Robostix register from the Beagleboard:

root@beagleboard:/usr/local/bin# i2c-io --dev /dev/i2c-2 0xb readreg 0 0x02

frank

On Nov 18, 9:54 am, Bill Gatliff <b.@billgatliff.com> wrote:

Anyone using i2c with the beagleboard? Perhaps from userspace, even?

b.g.