DS90UB928Q-Q1: remote I2C issue on 928

Betty Guo

Part Number: DS90UB928Q-Q1

Hi team,

customer applicaiton is host <-->927<-->928<-->display, the I2C communicate between host and 927 is work, but they can't reomote communicat with 928.

we have check the I2C address is correct. the IDx of 928 is connect to ground, the I2C address is 0x2C. the reg 0x03 of 927 is 0xda to enable pass thought.

any others reg need to be enable?

by the way, I'm a little confused with reg0x06,reg0x07and reg 0x08.what the difference among these reg? and for remore I2C control, how to configure them?

thanks.

over 4 years ago

0 Hamzeh Jaradat over 4 years ago

TI__Guru** 108460 points

Hello Betty,

If remote is not working, can you at least communicate with the 928 using it's local I2C bus?

0 Betty Guo over 4 years ago in reply to Hamzeh Jaradat

TI__Expert 7300 points

yes host can read/write 928 by I2C directly, but failed via LVDS . I2C address of 928 is 0x58.

And, I let customer read reg 0x06 Deser ID of 927, it is 0x00, not 0x58. What the next to debug?

Any hardware design may caused this issue?

Thanks

0 Hamzeh Jaradat over 4 years ago in reply to Betty Guo

TI__Guru** 108460 points

Just to summerize, 927 can be reached via I2C locally. Same thing to 928 also local I2C is working. But remote in both direction is not working, correct?

In the 928, you may check register 0x01[2] to make sure the back channel is enabled!

0 Betty Guo over 4 years ago in reply to Hamzeh Jaradat

TI__Expert 7300 points

Hi Hamzeh,

host <--->927<----------->928

927 can be reached via I2C locally --- yes

928 can be w/r via local I2C --yes

The issue is host can't be w/r 928 via LVDS(927)

0 Hamzeh Jaradat over 4 years ago in reply to Betty Guo

TI__Guru** 108460 points

Thanks for confirmation.

Can you check the BC enable as said above?

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DS90UB928Q-Q1: remote I2C issue on 928