I would take that down to 4.7k. Not sure that it will fix your issue, but a
stronger pullup is generally required.

Gerald



On Wed, Sep 3, 2014 at 12:46 AM, Prakash Parmar <[email protected]>
wrote:

> Hi,
> Thanks for reply.
>
> The pullup resistor which is using in I2C Bus is 10K with 3.3V.
>
> Regards,
> Prakash
>
>
> On Wed, Sep 3, 2014 at 12:10 AM, Gerald Coley <[email protected]>
> wrote:
>
>> What size pullup resistors are you using on the I2C bus?
>>
>> Gerald
>>
>>
>> On Tue, Sep 2, 2014 at 12:29 PM, <[email protected]> wrote:
>>
>>> Hi !!
>>>
>>> I'm facing problem with Custom I2C cape. It's I/o Expander using NXP's
>>> PCF8574T Expander chip. I'm unable to detect it. I tried every thing
>>> available on web. Can you help me ? please ?
>>>
>>> Here is some output.
>>>
>>> root@beaglebone:~# uname -a
>>> Linux beaglebone 3.8.13 #1 SMP Wed Sep 4 09:09:32 CEST 2013 armv7l
>>> GNU/Linux
>>>
>>> root@beaglebone:~# i2cdetect -y -r 0
>>>      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
>>> 00:          -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 20: -- -- -- -- UU -- -- -- -- -- -- -- -- -- -- --
>>> 30: -- -- -- -- 34 -- -- -- -- -- -- -- -- -- -- --
>>> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 50: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 70: -- -- -- -- -- -- -- --
>>> root@beaglebone:~# i2cdetect -y -r 1
>>>      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
>>> 00:          -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 10: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
>>> 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 50: -- -- -- -- UU UU UU UU -- -- -- -- -- -- -- --
>>> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 70: -- -- -- -- -- -- -- --
>>>
>>> root@beaglebone:~# i2cdetect -y -r 2
>>>      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
>>> 00:          -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 20: 20 -- 22 -- 24 -- 26 -- -- -- -- -- -- -- -- --
>>> 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
>>> 70: -- -- -- -- -- -- -- --
>>>
>>> I'm using Beaglebone Black Rev B.
>>>
>>> Hope Listen form you soon.
>>> Thanks.
>>>
>>> On Thursday, July 17, 2014 9:17:40 PM UTC+5:30, Johan Korten wrote:
>>>>
>>>> I managed to make my own cape (for two XBee modules). It works very
>>>> well (even sending between the two modules and to the third one on the
>>>> computer), but:
>>>>
>>>> if I use node ./eeprom.js
>>>>
>>>> I suspect that my cape is expected to be connected to the fourth (or
>>>> third if you start counting at 0) i2c bus:
>>>>
>>>> /sys/bus/i2c/drivers/at24/3-0057/eeprom instead of
>>>> /sys/bus/i2c/drivers/at24/1-0057/eeprom
>>>>
>>>> So should I fix that in my cape (my cape is default at
>>>> /sys/bus/i2c/drivers/at24/1-0057 but can be configured to go from
>>>> /sys/bus/i2c/drivers/at24/1-0054 .. /sys/bus/i2c/drivers/at24/1-0057)
>>>>
>>>> Apart from that, I managed to program the eeprom and get it working,
>>>> but since it uses UART 2 and UART 5 I needed to change /boot/uboot/uEnv.txt
>>>> to get that working (BBB Rev B so that is why I needed to
>>>> change /boot/uboot/uEnv.txt instead of /media/BEAGLEBONE/uEnv.txt),
>>>> but do I need to supply that with my final version somewhere or is it
>>>> enough to put that in the manual?
>>>>
>>>> Sincerely,
>>>> Johan
>>>>
>>>>  --
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