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SMARTRFTRXEBK: Connecting an External MCU over UART

Other Parts Discussed in Thread: CC1120

We want to connect our prototype board via UART to the SMARTRF TRXEB so we can control the CC1120 EM board on the TRXEB using the MCU on our board.

Our prototype board exposes a UART port.

I know that we can control CC1120 EM board by hooking up the SPI and GPIO pins connector P7 of the TRXEB, but it is possible to connect using the UART TX and RX pins that are exposed from our board?

I basically want to bypass the MSP430 and talk to the CC1120 in a similar way to Smart RF mode, but I don't want to connect via SPI lines as I cannot cut tracks on my board and re-route SPI and GPIO lines.



  • I believe the short answer is no.

    You need SPI to communicate with CC1120 and hence you need a UART to SPI conversion. This is in effect the MSP on the TRXEB since this uses USB to SPI.

    But I would assume that you want to use the prototype board to develop code for a CC1120 based system. For this you would want to use SPI directly since doing UART to SPI gives a latency which could cause timing issues.

    Why do you want to use this prototype board when it's not designed for the task (no SPI interface)?
  • This is an interim solution. We are redesigning our board with the CC1120, but samples will be available several weeks from now. In the interim, we wanted to see if we can quickly hook on the TRXEB without hacking cutting tracks and connecting lines on our board. Anyway, that's probably what I will attempt to do - we already have another board with CC1120 drivers working, but the current board has a different MCU. So, we do need to port that driver and get he SPI working.
  • Instead of hacking the board, would you be able to get hold of a eval board for the MCU with the SPI exposed?
  • Yes, an eval board would be ideal, but its not an option for us as the board is designed by a third-party manufacturer in China using an MCU from a Chinese chip vendor. We don't have any direct communications with this vendor.