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DS90UB954-Q1: How to change from synchronous clock mode to asynchronous clock mode

Tomoaki Yoshida91
Genius 5255 points

Part Number: DS90UB954-Q1

Hi team,

Please tell me how to change from synchronous clock mode to asynchronous clock mode at 954.

I understand that it can be selected at startup by voltage setting of MODE terminal.

I'd like to know if it can be switched with a register like 953.

We want to use both synchronous mode and asynchronous mode using the same hardware.

And we do not consider switching dynamically while operating it.

Boards used asynchronously are always used asynchronously, but I do not want to change the resistance of the MODE terminal for each board.

Since 953 can be changed asynchronously in the register setting, I thought that 954 could be changed by register as well, but I could not find it in the datasheet.

954 can not set the mode with a register like 953?

Best regards,

Tomoaki Yoshida

  • 0
    TI__Guru** 116930 points
    Hello,
    this depends on the first level on the Serializer. the Serializer must be set to Synch or Asynch mode. once the Serializer is set on the right mode, you will need to change the value of 0x58[2:0] on the Deserializer to match the SER.
  • 0 in reply to Hamzeh Jaradat
    Genius 5255 points

    Hi Hamzeh-san,

    Thank you for your support.

    Now we are switching to asynchronous mode after starting with 953-954 board set MODE terminal voltage for synchronous clock mode.

    We wrote the register 0x03[2:0] of 953 to 010 through back channel from 954 after start up.

    Then, 953-954 link down occurs, so I think that it is necessary to switch the MODE of 954.

    In order to change the mode of 954, do I have to change the strap resistance according to the table below?

    Or if Reg 0x58[2:0] of 954 is changed to an appopriate value, is it not necessary to change RX MODE?

    Best regards,

    Tomoaki Yoshida

  • 0 in reply to Tomoaki Yoshida91
    TI__Guru** 116930 points
    Hello Tomoaki-san,

    on the 954 it should be enough if you change the mode on reg 0x6D[1:0] and the Back channel speed on reg 0x58[2:0].
    but on the 953 if you want to use the asynch mode you need to use an external clock source (oscillator). the asynch mode does not use the back channel clock.