CC1200: CC1200 FIFO Error Issue in Synchronous Serial Mode

Part Number: CC1200

Test Scenario - CC1200 is operating in Synchronous serial mode and we are using bit banging SPI communication for CC1200 configuration changes.


  1. When we keep switching between RX and TX mode of CC1200 using SRX and STX commands, the RX_FIFO_ERROR is observed in MARC_STATE register.
  2. When above error comes up, the MODEM_STATUS0 register shows that RX_FIFO_EMPTY and RX_FIFO_UNDERFLOW flags are set in it.
  3. The PKT_CFG and MDM_CFG registers still reflect that CC1200 is in Synchronous serial mode and RX_FIFO is disabled.


Kindly let us know, if there is any possibility by which in synchronous serial mode, the CC1200 will try to read RX FIFO(ideally it should not use FIFOs in Synchronous serial mode)?

When the FIFO Error is observed, all the configuration registers still reflects that CC1200 is working in Synchronous serial mode, then why RX FIFO is being read?

  • Hi Harshal, 

    Thanks for your question, we are looking into this and will get back to you when we have an update.


  • I think it is correct that some of the FIFO flags are set for some reason, even if the radio is in sync mode. This should however not affect the serial operation.

    The only thing you need to remember is that if you for some reason have an application that switches between serial mode and normal FIFO mode, you should reset the device when going from serial to FIFO mode, to make sure that all flags are cleared and that FIFO pointers etc. are in their default positions.



  • It does affect the system. Due to FIFO Error(which should not get triggered in sync mode)  CC1200 stops communication and does not Transmit/Receive any new data on RF communication if this error flag is set in MARC_STATE.

    We have to manually set CC1200 to Idle mode and then this flag gets cleared. Only using this work around we are able to maintain RF communication on CC1200.(ideally if these flags does not impact then CC1200 shall continue to TX/RX in sync mode without any issue even after FIFO ERROR).

  • Please provide me with your settings (and other necessary information) to enable me to reproduce the problem on my side.