DS90UB925Q-Q1: Missing information about TX ID

Sergey Popov2

Part Number: DS90UB925Q-Q1
Other Parts Discussed in Thread: DS90UB926Q-Q1

Good afternoon!
There is a small ambiguity. We are our task - to transfer the image from the camera to the processor. Therefore, the sensor is connected to the DS90UB925Q-Q1, and the processor to the DS90UB926Q-Q1. The configuration, of course, is performed by the processor. Communication on I2C works well. I can read and write registers like
DS90UB926Q-Q1 (local), and DS90UB925Q-Q1 (remote). But ... Registers 0xf0 - 0xf5 (TX ID DS90UB925Q-Q1) give out 0. Why? The remaining registers are written and read correctly. What am I doing wrong?
Thank you

over 7 years ago

0 Palaniappan Manickam over 7 years ago

TI__Genius 10475 points

Hello,
Are you having issues with reading only this register? Can you confirm the LOCK is high during I2C access to these registers?

You can monitor the CRC backchannel error register to make sure there are no errors in communication.

0 Sergey Popov2 over 7 years ago in reply to Palaniappan Manickam

Intellectual 405 points

Good afternoon!
Yes, reading only these registers causes suspicion. I, of course, control the signal status of the LOСK (and register 0x1c DS90UB926) and control the register 0x0a, 0x0b DS90UB925. There are no errors. Locally read the identifier DS90UB925 did not try.
Thank you

0 Vishy Viswanathan over 7 years ago in reply to Sergey Popov2

TI__Mastermind 21685 points

Sergey,

Processor would need to support clock (SCL) stretching for remote slave accesses. Please refer following app note: SNLA131

Thanks, Vishy

0 Sergey Popov2 over 7 years ago in reply to Vishy Viswanathan

Intellectual 405 points

Good afternoon!
My receiver and transmitter are on the table and are connected by a wire, not longer than 30cm. In any case, why do other registers be read correctly and errors occur during the exchange?

Thank you

0 Vishy Viswanathan over 7 years ago in reply to Sergey Popov2

TI__Mastermind 21685 points

Sergey,

I checked on this using UB925 and UB926 EVMs. The EVMs are locked and then I check reading from UB925 side reading UB926 ID registers (remote read). This was successful. But from UB926 side, reading UB925 ID registers returned 0. I understand in IVI systems processor is on the serializer side and so this might be intentional to prevent remote host on the deserializer side from changing serializer id.

Thanks,
Vishy

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DS90UB925Q-Q1: Missing information about TX ID