DS90UB953-Q1: lose communication during the initialization

we need your recommendation in order to perform any test or measurement before to proceed with ABA test, we need to avoid lost evidence

Hello Oscar,

I need more details. It looks like you are connecting a 953 camera module to some deserializer on the ECU module. Do you know what deserializer is being connected?

And where are the I2C communications failing? When the ECU talks to the deserializer? The serializer? Or the image sensor?

Oscar Ramos said:

Failed, the LVDS Signals are dropping when the failure presents

Which LVDS signal are you talking about? Are you talking about LOCK being lost between the Serializer and Deserializer?

Oscar Ramos said:

Voltaje Failed, the DLANE 2 P don’t have voltage (pin 31 CSI_D2P)

Could you elaborate what this means? 

Are you probing these pins and getting 0V?

This typically happens if the MIPI transmitter (for example the image sensor) is not powered properly and is not outputting any voltage.

Best,

Justin Phan

hich LVDS signal are you talking about? Are you talking about LOCK being lost between the Serializer and Deserializer? pins 1, 2, 3, 4 from 953 device, Signals are dropping when the failure presents

Do you know what deserializer is being connected? DS90UB954Q

Could you elaborate what this means? known good unit .60V / suspect unit .03V

Hello Oscar,

Oscar Ramos said:

known good unit .60V / suspect unit .03V

Are you probing these MIPI CSI signals with a high-speed probe? Can you able to provide an image of the scope captures?

We typically expect the signal to look like below:

In Low Power (No data transmission), we expect the voltage to be around 1.1V. In active data transmission, we expect a differential voltage between 140mV to 270mV, with a common-mode voltage between 150mV to 250mV. Are you seeing something similar in your passing or failing cases?

The 953 is also just acting as a MIPI receiver. When it receives video data by the MIPI transmitter, it will enable termination and receive the data. Can you confirm that all of the 953 power rails are stable and that the power-up sequence has been followed?

Best,

Justin Phan

Hi Justin,

we will take your recommendations and come back soon, 

thank you,

Okay, please let me know when you can share more information on the scope captures and measurement setup.