Use an I2C bus gpio I/O Port in linux

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Use an I2C bus gpio I/O Port in linux

Contributor II

Hi, all.

I'm working with a MBa6ULX board which have an TQMA6ULx. The board has an 8bit I/O port i2c with three buttons. I'm trying to get the status of these buttons by console. The I2c device has 0x21 address. Captura.PNG

If I execute the command i2cdetect -y 3  I get the next info:


If I try to read the registers of the 0x21 device:


Why I get the UU in the address of my I2C devices?

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NXP TechSupport
NXP TechSupport

Hi Santiago,

I have found the following interpretation of the "UU" output on a Linux man page:

"UU". Probing was skipped, because this address is currently in use by a driver. This strongly suggests that there is a chip at this address.

I am not able to reproduce the issue of the i2c detect command, since we do only support our Linux BSP and boards. I would suggest you to get in contact with TQ so they help you more properly to address the solution to your problem using their board:

TQ support enquiry

You can also try to debug the I2C bus using a logic analyzer to determinate whether the device does respond  with an acknowledge or find out if a wiring problem exists.  

Best regards,


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