In my boot log, it also has this: i2c_omap i2c_omap.3: bus 3 rev3.12 at 400 kHz. 

So does it mean the i2c bus should work well? 

I double checked the pins i am using, they are at right place. And i dont have any other devices on i2c bus. 


On Mon, May 10, 2010 at 9:42 PM, Dave Hylands <dhylands@gmail.com> wrote:

On Mon, May 10, 2010 at 7:51 AM, SHI yifei <shiyifei1@gmail.com> wrote:
> Hi Dave:
> I groundded A0-A2, so the address i am passing is 0x20. However, after i use
> i2c detect, it turned out 0x50. 

That's probably another device on the bus.

If the SDA and SCL lines aren't changing then there's no way that i2cdetect could be seeing your device.

> The daughter board i am using is Summit. and the pins are  23(scl) and
> 24(sda).
> When you connect your overo to a robostix through i2c, do you need to
> configure the module, enable the i2c controller or do this sort fo things in
> 18.5 in Technical Manual?

As far as I can remember, all I did was connect a voltage converter between the overo and the robostix.

I tried it again, and the robostix shows up properly when I run i2cdetect.

You should see lots of toggling on the SDA and SCL lines while i2cdetect is running.

You should also see the following line in your boot script:

i2c_omap i2c_omap.3: bus 3 rev3.12 at 400 kHz

In my boot log, it shows up just before the Bluetooth stuff. Here's a snippet of my log:

twl4030_usb twl4030_usb: Initialized TWL4030 USB module
regulator: VMMC1: 1850 <--> 3150 mV normal standby
regulator: VDAC: 1800 mV normal standby
regulator: VPLL2: 1800 mV normal standby
i2c_omap i2c_omap.3: bus 3 rev3.12 at 400 kHz
Bluetooth: Core ver 2.15
NET: Registered protocol family 31
Bluetooth: HCI device and connection manager initialized
Bluetooth: HCI socket layer initialized
cfg80211: Using static regulatory domain info
cfg80211: Regulatory domain: US
     (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
     (2402000 KHz - 2472000 KHz @ 40000 KHz), (600 mBi, 2700 mBm)
     (5170000 KHz - 5190000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
     (5190000 KHz - 5210000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
     (5210000 KHz - 5230000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
     (5230000 KHz - 5330000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
     (5735000 KHz - 5835000 KHz @ 40000 KHz), (600 mBi, 3000 mBm)
cfg80211: Calling CRDA for country: US

I guess that the other thing to double check is which exact pins you're using.

You mentioned using 23 and 24. The odd pins are next to the edge of the board, and the even pins are towards the inside of the board. There is a 1 and a 40 silkscreened on the board.

Dave Hylands
Shuswap, BC, Canada


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