DS90UB940-Q1: I2C not showing slave devices

David Dominguez Moises

I have my own set up of the DS90UB940 which is working fine. I can communicate through I2c Ser (DS90UB949 0x18) to/from DeSer (DS90UB940 0x2c).

I have several slaves on DeSer side, but I can see none of them on the Ser side.

I tried setting register 0x03 to 0xF8 and 0x05 to 0x9E on TI940 to allow all I2C pass-through but nothing seems to fix it.

Any ideas?

Thanks

over 7 years ago

0 Jiashow Ho over 7 years ago

TI__Genius 11340 points

Hi David,

Are you able to see the slave IDs in register 0x08 in the 940? If so, can you also set the slave alias in register 0x10? Try communicate to the slave from the 949 using the slave alias ID.

Best,

Jiashow

0 David Dominguez Moises over 7 years ago in reply to Jiashow Ho

Intellectual 570 points

Hi
All the slaves IDs on 940 are 0's. But connecting a raspberry directly to I2C bus I see salves at 0x50, 0x51, 0x52. Should this be set up in slave ids registers?

thanks,
David

0 Jiashow Ho over 7 years ago in reply to David Dominguez Moises

TI__Genius 11340 points

Hi David,

Yes. Try setting the slave IDs to 0x50, 0x51, and 0x52 to see if you are able to communicate to the the slaves.

Best,
Jiashow

0 David Dominguez Moises over 7 years ago in reply to Jiashow Ho

Intellectual 570 points

I tried doing that but it didn't help.

I also have a similar set up with a DS90UB948 and that one is working. It doesn't have the slave Ids registers populated and still is able to talk to remote slaves.

I think the microcontroller we have besides the TI948 may be causing any I2C issues.

Best,

David

0 Jiashow Ho over 7 years ago in reply to David Dominguez Moises

TI__Genius 11340 points

Thanks for the update David!

It's definitely worth looking into the microcontroller since another similar setup is working.

Best,
Jiashow

0 David Dominguez Moises over 7 years ago in reply to Jiashow Ho

Intellectual 570 points

At the end I check our board. Turns out a cypress chip on the board was blocking i2c bus causing our failures. Now it is working.

Thanks for the support,

David

0 Vijaya Ceekala over 7 years ago in reply to David Dominguez Moises

TI__Intellectual 2930 points

David

That is good to know. Please close the ticket if your issue has been resolved

Regards

Vijay

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DS90UB940-Q1: I2C not showing slave devices