TRF372017: SPI Control Issue

Part Number: TRF372017
Other Parts Discussed in Thread: LMX8410L,

Hello,

We have some SPI control issues on TRF372017 & LMX8410L.

Can we use  “Daisy Chain” to control these ICs  as follow cases?

case1) 2 pcs of TRF372017, 

case2) 2 pcs of LMX8410L,

case3) 2pcs of TRF372017 and 2pcs of LMX8410L simultaneously.

Block diagram of "Daisy Chain" control is shown below.



Thank you.

Best regards,
Alan Ke

  • Hi Alan,

    The SPI bus of the TRF372017 cannot support daisy chain. 

    SPI in general:

    1. you can have separate CS pin for different TRF372017. If you have two TRF372017, then you have two separate CS pin.

    2. the SCLK, SDIO, and/or SDO (in 4 wire mode) can be shared amongst the TRF372017.

    3. When talking to first TRF372017, simply trigger the CS pin of the first TRF372017 to logic low while the CS pin of the 2nd TRF372017 to logic HI. Vice versa for the 2nd TRF372017

    I will let other team member on the CTS team to comment on the LMX device.

    -kang

  • Hi Alan,

    Echoing what Kang has said, LMX8410L does not support SPI daisy-chaining as written. You will need to supply each device with its own chip select line; other lines can be shared. For chip selects, you might consider a demux or a shift register with output enable control.

    Regards,

    Derek Payne