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DS90UB960-Q1: Remote I2C rate and SPI/UART rate

Johnny Guo
Expert 4910 points

Part Number: DS90UB960-Q1

Hi, team,

I would like to confirm some question about data rate for remote I2C and SPI/UART through GPIO.

  • The Ser is 933 or 953, the Des is 960
  • Customer will use I2C and SPI/UART to do remote control and communication

Questions:

1. Can you confirm what is the maximum remote I2C rate of 953/960 and 933/960? There is on app note below for some explanation, but we don't have further information.

https://www.ti.com/lit/an/snla131a/snla131a.pdf?ts=1652943374406&ref_url=https%253A%252F%252Fwww.ti.com%252Fsitesearch%252Fen-us%252Fdocs%252Funiversalsearch.tsp%253FlangPref%253Den-US%2526searchTerm%253Dsnla131%2526nr%253D51

2. If we send SPI/UART through GPIO, what is the max communication data rate for 933/960 and 953/960?

I copy customer into this threads and looking forward to your reply. 

Thanks.

Johnny

  • +1
    TI__Mastermind 33240 points

    Hello Johnny,

    1. If your setup is something like SoC->960->933/953, then the local I2C rate is dependent on the host SoC. The 960 datasheet states that it supports I2C speeds up to Fast-Mode Plus (1MHz). When an I2C command is sent to the remote serializer, the serializer will regenerate the I2C command on its local bus, with the serializer acting as a proxy Master. The serializer will regenerate the timing of the SCL pulse through register settings. For example, you can set the SCL high time and SCL low time of the SCL pulse period through registers 0x0B and 0x0C in the 953. You can find more details in the serializer datasheets.
    2. You can send SPI/UART signals from a local processor to remote device through the GPIO pins on the connected SER/DES devices. The max communication rate depends on the sampling rate on the GPIOs. The sampling rate on the GPIOs depends on your device configuration and we recommend the sampling rate be 4x higher than the frequency of the signal. If you are sending the SPI/UART signal over the Back Channel (SoC->DES->SER->Target Device), then you can see Table 7-5 in the 953 datasheet for the max allowed signal frequency.
      2. If you are sending the SPI/UART signal over the Forward Channel (SoC->SER->DES->Target Device), then you can look at Table 7-4 in the 953 datasheet for max recommended frequency.

    Best,

    Justin Phan

  • 0 in reply to Justin Phan
    TI__Expert 4910 points

    Thank you Justin, very helpful.