57.7.8.16.1 Host Node Configuration

The user can choose between two DMA modes by configuring the FLEX_US_LINMR.PDCM bit:

  • PDCM = 1: The LIN configuration is stored in the WRITE buffer and it is written by the DMA in the Transmit Holding register FLEX_US_THR (instead of the LIN Mode register FLEX_US_LINMR). Because the DMA transfer size is limited to a byte, the transfer is split into two accesses. During the first access, the NACT, PARDIS, CHKDIS, CHKTYP, DLM and FSDIS bits are written. During the second access, the 8-bit DLC field is written.
  • PDCM = 0: The LIN configuration is not stored in the WRITE buffer and it must be written by the user in FLEX_US_LINMR.

The WRITE buffer also contains the Identifier and the data, if the USART sends the response (NACT = PUBLISH).

The READ buffer contains the data if the USART receives the response (NACT = SUBSCRIBE).

Figure 57-51. Host Node with DMA (PDCM = 1)
Figure 57-52. Host Node with DMA (PDCM = 0)