SPRUJ17H March 2022 – October 2024 AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1
The receive module automatically calculates the CRC on the incoming data. The received CRC value is placed into RX_CRC_INFO.RX_CRC. The CRC value calculated by hardware on the received data is placed into RX_CRC_INFO.CALC_CRC. These values are compared by hardware and RX_EVT_STS_ALT1_.CRC_ERROR is set if there is a mismatch. The receiver can generate an interrupt based on RX_EVT_STS_ALT1_.CRC_ERROR if enabled.
Since the CRC is only used in data frames, the values found in RX_CRC_INFO.RX_CRC and RX_CRC_INFO.CALC_CRC are undefined during ping and error frames.
For more information on how the CRC is calculated, refer to Section 7.4.8.3.7.
If the transmitting module is sending a software-defined CRC value (FSITX.TX_OPER_CTRL_LO_ALT2_.SW_CRC = 1), the receiver module triggers a CRC error event if the received value does not match the hardware-calculated value. As this is an application-level decision, the FSIRX can safely disregard the CRC error event. Application software needs to calculate and verify the incoming CRC using the same custom algorithm used on the transmitter and act appropriately.
The CRC field can also be used as an application-specific value, not a CRC. The application can use the RX_CRC_INFO.RX_CRC as required. All CRC errors and flags can be ignored in this situation.