Message RAM Configuration

The Message RAM has a width of 32 bits. The MCAN module can be configured to allocate up to 4352 words in the Message RAM. It is not necessary to configure each of the sections listed in the figure below, nor is there any restriction with respect to the sequence of the sections.

When operated in CAN FD mode, the required Message RAM size depends on the element size configured for Rx FIFO0, Rx FIFO1, Rx Buffers, and Tx Buffers via MCAN_RXESC.F0DS, MCAN_RXESC.F1DS, MCAN_RXESC.RBDS, and MCAN_TXESC.TBDS.

Figure 1. Message RAM Configuration

When the MCAN addresses the Message RAM, it addresses 32-bit words, not single bytes. The configurable start addresses are 32-bit word addresses; i.e., only bits 15 to 2 are evaluated, the two least significant bits are ignored.

Note: The MCAN does not check for erroneous configuration of the Message RAM. The configuration of the start addresses of the different sections and the number of elements of each section must be checked carefully to avoid falsification or loss of data.