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Part Number: LAUNCHXL-CC3235SF
Other Parts Discussed in Thread: CC3220SF, CC3235SF, CC3230SF

Tool/software: Code Composer Studio

I used the spislave sample code with TI-RTOS and compiled by CCSv9.2. The issue is it can send transaction.txBuf via SPI_transfer(slaveSpi, &transaction), but cannot receive transaction.rxBuf.(no any data be received). I used spimaster sample code, both of transaction.txBuf and transaction.rxBuf work well. (I used cc3235sf as SPI master connected with cc3220sf as slave last week. It has the same issue on cc3220sf that spislave sample code cannot receive transaction.rxBuf)

  • Hi Jonathan,

    Running the spimaster and spislave examples together with two CC3220 launchpads, I am unable to replicate issue you are seeing. 

    Are you using the latest SDK? If not, you can download it from here:

    Also, have you double-checked that you have wired all of the needed SPI and GPIO signals between the two launchpads? The readme.html file in the example gives instructions on what to connect. Please be sure that you use as short of a wire as possible for the SPI clock signal, to prevent any issues arising from a malformed clock on the slave side.

    Have you tried reducing the SPI clock speed, to see if that might help? The SPI clock is set to 10MHz default, but try changing it to 1MHz.

    If all that fails, if you could capture the SPI signal with an oscilloscope and provide that to me that may be helpful in debugging the issue you are seeing.



  • Dear Jan,

    1. I've used the same SDK as you provide.

    2. My CC3220SF has been locked (the other issue, not fix yet), so I could not connect with CC3235SF to re-do the test.

    You can see the below pictures. The issue is in Slave mode, CC3230SF/CC3235SF cannot read MOSI data.

    But CC3235SF work in Master mode, both of MOSI and MISO are working well.

    * CC3235SF (Slave)-external MCU(Master)---MOSI cannot be read by CC3235SF in slave mode, the same issue as CC3220SF:

    * CC3235(Master), MOSI loop back to MISO, it can be read by CC3235SF in Master mode.

  • Hi Jonathan,

    Other than the momentary glitch in the SPI CS line in your first screenshot, the logic analyzer captures look correct.

    To clarify, when you perform your SPI transfer test between your master and slave running on two launchpads, which buffers were incorrect?

    Was the master transaction.rx buf incorrect too? Or was it only the slave transaction.rxbuf that was incorrect?



  • Hi Jonathan,

    I assume that you have resolved your issue since I have not heard back from you. If not, feel free to post a response to this thread, or open a new thread regarding this issue.