DS90UB953-Q1: I2C in the back channel

Shlomi Yehezkia

Part Number: DS90UB953-Q1
Other Parts Discussed in Thread: TCA9546A,

Hi Team,

Refer to DS90UB953-Q1, I want to use I2C in the back channel, is it possible to connect translating switch control (TCA9546A) between local I2C slaves and the DS90UB953-Q1? (see attached drawing)

Do I need to enable the i2c_pass through all bits (bits 7,6 @ of BCC_CONFIG (address 0x32)?

Thanks,

Shlomi

DS90UB953-Q1.docx

over 6 years ago

0 Casey McCrea over 6 years ago

TI__Guru** 103215 points

Hello Shlomi,

I do not see support for I2C clock stretching in the TCA9546A datasheet so I do not believe we can support it since the 954/953 require clock stretching to work over the back channel. What voltage level are you trying to support for the slave devices attached to the 953? Please note that 953 can support both 1.8V and 3.3V I2C.

Best Regards,

Casey

0 Shlomi Yehezkia over 6 years ago in reply to Casey McCrea

Mastermind 6150 points

Hi Casey,

I need to support both 3.3V & 1.8V I2C slave devices.

Thanks,

Shlomi

0 Casey McCrea over 6 years ago in reply to Shlomi Yehezkia

TI__Guru** 103215 points

Hello Shlomi,

I would suggest an alternative device that can support I2C clock stretching. This may work for you as an example: http://www.ti.com/lit/ds/symlink/tca9802.pdf

Best Regards,

Casey

0 Shlomi Yehezkia over 6 years ago in reply to Casey McCrea

Mastermind 6150 points

Hi Casey,

Please advise, if slow communication (I2C & GPIOs) between DS90UB953A & DS90UB954 can be done in forward channel or back channel without active MIPI.

Thanks,

Shlomi

0 Casey McCrea over 6 years ago in reply to Shlomi Yehezkia

TI__Guru** 103215 points

Hello Shlomi,

The answer is yes. It has already been answered before here: https://e2e.ti.com/support/interface/f/138/t/700640?tisearch=e2e-sitesearch&keymatch=fpd%2525252520link%2525252520i2c%2525252520without%2525252520image

Best Regards,

Casey

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DS90UB953-Q1: I2C in the back channel