SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
The CAN controller conforms to the CAN protocol version 2.0 (parts A and B). Message transfers that include data, remote, error, and overload frames with an 11-bit identifier (standard) or a 29-bit identifier (extended) are supported. Transfer rates can be programmed up to 1 Mbps.
The CAN module consists of three major parts:
A data frame contains data for transmission, whereas a remote frame contains no data and is used to request the transmission of a specific message object. The CAN data frame or remote frame is constructed as shown in Figure 11-2.
The protocol controller transfers and receives the serial data from the CAN bus and passes the data on to the message handler. The message handler then loads this information into the appropriate message object based on the current filtering and identifiers in the message object memory. The message handler is also responsible for generating interrupts based on events on the CAN bus.
The message object memory is a set of 32 identical memory blocks that hold the current configuration, status, and actual data for each message object. These memory blocks are accessed using either of the CAN message object register interfaces.
The message memory is not directly accessible in the MSP432E4 memory map, so the CAN controller provides an interface to communicate with the message memory using two CAN interface register sets for communicating with the message objects. These two interfaces must be used to read or write to each message object. The two message object interfaces allow parallel access to the CAN controller message objects when multiple objects may have new information that must be processed. In general, one interface is used for transmit data and one for receive data.