SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
Once the CSI2 receiver has read the Data Payload, it reads the checksum in the Packet Footer. In the generic case, the length of the Data Payload is a multiple of 8-bit data words. In addition, each data format may impose additional restrictions on the length of the payload data, e.g. multiple of four bytes. Each byte is transmitted LSB first.
To detect errors in transmission of the payload of long packets, a 16-bit CRC checksum is computed on the payload of the long packets in the transmitter. This CRC is stored in the packet footer. The CSI2 receiver checksum is compared against the CSI-2 transmitter checksum. If the checksum does not match, an interrupt is triggered.
CRC errors are logged in the CAL_CSI2_VC_IRQSTATUS_l[] CS_IRQ_x (where x = [0 to 3]) register bit-fields. Logging cannot be disabled, but SW can configure the corresponding bit in the CAL_CSI2_VC_IRQENABLE_l register to prevent event generation at a higher level.
Since the payload has been already transferred into memory, it is not possible to discard the data but only to generate an interrupt.