This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DS90UB948-Q1: I2C and SPI communication problems of DS90UB948

Part Number: DS90UB948-Q1

Hi team:

Our mode uses DS90UB948 and DS90UB949 paired, the MCU is connected to the I2C interface of DS90UB949, the I2C bus behind DS90UB948 is connected to multiple slave devices, and the SPI interface of DS90UB948 is also connected to one slave device.
Our purpose is to use both the SPI and I2C interfaces of the DS90UB949. Is it feasible?
My question is:
1. If DS90UB949 and MCU only have I2C interface, can DS90UB948 convert the I2C signal sent by DS90UB949 to SPI signal to communicate with the slave device?
2. If the MCU is connected to the I2C and SPI interfaces of the DS90UB949, can the SPI and I2C interfaces of the DS90UB948 be used at the same time? If they cannot be used at the same time, is it possible to use these two interfaces in a time-sharing manner?
3. If the above two methods are not feasible, is there a recommended way to implement it?

  • Hello,

    You can certainly use both SPI and I2C interfaces on the 949 device, however see my feedback below:

    1. The UB948 cannot convert the I2C signal sent by the UB949 to SPI. The UB948 can however receive SPI from the UB949
    2. Both the I2C and SPI can be used on the UB948, however as I mentioned above, the SPI and I2C signals received from the UB949 are completely separate.
    3. If using SPI is a requirement for you, I have two suggestions (suggestion "a" is probably the better of the two):
      1. Send both an SPI and I2C signal from the UB949 to the UB948. This would entail either having both an I2C master AND SPI master feeding into the UB949 OR externally convert the I2C signal to SPI.
      2. The I2C signal from the 948 could be externally converted to SPI.


    Ben Dattilo

  • Thank you for your answer!
    If I adopt your suggestion "a", I2C and SPI can communicate at the same time, and they do not affect each other, right? Is bidirectional communication possible with both SPI and I2C?

  • Hello,

    That is correct, you should be able to communicate at the same time without the two signals affecting each other. Both I2C and SPI have forward and reverse channel operation.



  • Got it, thanks a lot!