Use I2C3 on beagle board without display

I was wondering if the dvi-chip or dvi-driver may interfere, so I tried to comment the video-related boot arguments in the env.txt and to disable the dvi-chip as described here: https://groups.google.com/forum/#!msg/beagleboard/ehPaVYoHd5s/XBogoz6al0kJ

Unfortunately that didn’t change anything.
I also checked the data sheet of the OMAP35xx processor if it could be possible to double mux the i2c-pins, but it seems that only one pin can set to the i2c-function.
Below the pin register table, they write:

For proper functioning of the following modules, CONTROL_PADCONF_x.INPUTENABLE must be set to 1 for pads configured to drive
output clocks:

But this should be the case according to the configuration I send earlier.

Is it reasonable that there may be a conflict with the DVI-system at all??

Hi Soja!

I have posted that thread about problems with I2C-2 lines on BB rev C4 (https://groups.google.com/forum/?fromgroups=#!searchin/beagleboard/krcevina/beagleboard/p_qggSIdmoE/R-PiPwht1BkJ).

If you can, connect your BB on Internet and download and instal i2c-tools program and then run it as here: http://yetanotherhackersblog.wordpress.com/2011/04/07/interfacing-the-beagleboard-with-an-srf08-ultrasonic-ranger-over-i2c/

It helped me a lot to determine what was my problem.

Regards,
Vojislav

четвртак, 29. новембар 2012. 12.06.17 UTC+1, Soja је написао/ла:

Hi Vojislav,

Thank you for your help.
I am actually using i2cdetect to check for my devices. The devices on the i2c2 show up fine and the scanning through the address space is fast.
But for the i2c3 the scanning of each address takes about a second and in dmesg a timeout message appears:

`
omap_i2c omap_i2c.3: controller timed out

`

If I dont connect anything to the i2c-bus, just an oscilloscope (and the level converters with pull-ups), I can see the clock and data signal for i2c2. For i2c3 however the signal is always high.

Best regards,

Jan

Only time when I’m getting that kind of timeout messages when working with my I2C-2 line is when my slave (PIC microcontroller) isn’t powered and I’m trying to sent some data to it. Actually, when I think better, the same power source is used for PIC and for Vin1 of my converters (TI 0102). Vin2 is powered from 1V8 on expansion board on BB.

I have never worked with I2C-3 on BB, so my knowledge on that issue is limited.

You will certainly solve your problem, it’s just matter of time.

Good luck!

четвртак, 29. новембар 2012. 13.37.21 UTC+1, Soja је написао/ла:

Only time when I'm getting that kind of timeout messages when working with
my I2C-2 line is when my slave (PIC microcontroller) isn't powered and I'm
trying to sent some data to it. Actually, when I think better, the same
power source is used for PIC and for Vin1 of my converters (TI 0102). Vin2
is powered from 1V8 on expansion board on BB.

Power is connected and the chips are running, if I connect them to i2c-2.

I have never worked with I2C-3 on BB, so my knowledge on that issue is
limited.

You will certainly solve your problem, it's just matter of time.

I hope so. Nevertheless my main problem is atm that I don't really know how the DVI interface is supposed to work and how (potentially) disable it. On monday I will test the pins as normal GPIOs to verify that my solder joints are working. In the mean time I hope that someone with more knowledge than me will show up :slight_smile:

Good luck!

Thank you.