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DS90UB925Q-Q1: Use Ds90ub940 instead of ds90ub926 with ub925

Part Number: DS90UB925Q-Q1

We need to deserialize signal from a oem device with ub925 to output csi2 signal. Our ideal choice should be ub940. However, the oem device was designed used with ub926 with device address 0x6A, while the device address 0x6A is not listed in ub940 data sheet. How should we address the I2C communication in this case?

  • Hi Wei,

    As it is not listed, this is not an applicable device address for the UB940. In this case, the best option, if possible, would be to modify the UB925 to communicate with whichever address you select for the UB940, which looking at the UB940 datasheet, the address with the closest location would be 0x68 or 0x6C.

    Please let me know if you have any other questions or concerns.

    Thanks,

    Ryan

  • Hi Ryan,

    thank you for the reply. Since ub925 is on an oem device which is not designed or programmed by us, is there a way to change the device address of the deserializers paired with it so that the Ub940 can work with it properly? If not able to change anything on ub925 side, what should we do to make ub940 work with it? Can the pair work without proper i2c communication? As far as we know, with oem setup, ub925 and ub926 have i2c read/write communication upon booting up.

  • Hi Wei,

    Unfortunately, the addresses in the datasheet are the only ones available, as far as I am aware.

    Let me discuss internally if anyone knows for sure how important I2C communication is, or if there is a way to get around this issue, and I will let you know what I find by the end of the day Monday.

    Thanks,

    Ryan

  • Hi Ryan, 

    can you please also check what are the required register settings to use ub940 with ub925 to output csi2 yuv422 signal?

  • Hi Wei,

    After checking internally, I can confirm that there isn't really a way to get around the fact that the address used for the 926 is not present on the 940, and that it would not be possible to use these devices without I2C, as without I2C, its impossible to talk to the devices. The best recommendation I can give to redesign around the fact if possible.

    As for the UB940 settings needed for YUV422, register 0x6B needs to be configured for YUV422, the datasheet details how it should be configured.

    Please let me know if you have any other questions or concerns.

    Thanks,

    Ryan