SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
Table 26-743 shows how a receive object for remote frames can be initialized.
MsgVal | Arb | Data | Mask | EoB | Dir | NewDat | MsgLst | RxIE | TxIE | IntPnd | RmtEn | TxRqst |
---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | appl. | appl. | appl. | 1 | 1 | 0 | 0 | appl. | 0 | 0 | 0 | 0 |
A receive object for remote frames may be used to monitor remote frames on the CAN bus. The remote frame stored in the receive object will not trigger the transmission of a data frame. Receive objects for remote frames may be expanded to a FIFO buffer (see Section 26.10.4.7.5, Configuration of a FIFO Buffer).
UMask must be set to ‘1.’ The mask bits (Msk[28:0], UMask, MXtd, and MDir bits) may be set to “must-match” or to “don’t care,” to allow groups of remote frames with similar identifiers to be accepted. The Dir bit should not be masked in typical applications. For details, see Section 26.10.4.8.8, Reception of Remote Frames.
The arbitration bits (ID[28:0] and Xtd bit) may be given by the application. They define the identifier and type of accepted received remote frames. If some bits of the mask bits are set to “don’t care,” the corresponding bits of the arbitration bits will be overwritten by the bits of the stored remote frame. If an 11-bit Identifier (standard frame) is used (Xtd = ‘0’), it is programmed to ID[28:18]. In this case, ID[17:0] can be ignored. When a remote frame with an 11-bit Identifier is received, ID[17:0] will be set to ‘0.’
The data length code (DLC[3:0]) may be given by the application. When the message handler stores a remote frame in the message object, it will store the received data length code. The data bytes of the message object will remain unchanged.
If the RxIE bit is set, the IntPnd bit will be set when a received remote frame is accepted and stored in the message object.