Microchip Technology dsPIC33 Reference Manual

DS70005340A-page 1 HIGHLIGHTS This section of the manual contains the following major topics: 1.0 Introduction ....................................................................................................................... 2 2.0 CAN FD Message Frames................................................................... ...

DS70005340A-page 2  2018 Microchip Technology Inc. 1.0 INTRODUCTION CAN Flexible Data-Rate (FD) addresses the increasing demand for bandwidth on CAN buses. The two major enhancements over CAN 2.0B consist of: • Increased data field up to 64 data bytes (currently 8 bytes) • Option to switch to faster bit rate after ...

DS70005340A-page 3 CAN FD Protocol Module Message Reception • 32 Flexible Filter and Mask Objects • Each Object can be Configured to Filter either: - Standard ID and first 18 data bits or - Extended ID • 32-Bit Timestamp • The CAN FD Bit Stream Processor (BSP) implements the Medium Access Control of the CAN FD proto ...

DS70005340A-page 4  2018 Microchip Technology Inc. Figure 1-2 shows the System Block Diagram. Figure 1-2: System Block Diagram TX Handler TX Prioritization RX Handler Filter and Masks Timestamping Interrupt Control Error Handling Diagnostics CxTX CxRX Device RAM TEF Message Object 0 Message Object 31 • • • TXQ M ...

DS70005340A-page 5 CAN FD Protocol Module 2.0 CAN FD MESSAGE FRAMES The ISO11898-1:2015 describes the different CAN message frames in detail. Figure 2-1 through Figure 2-6 explain and summarize the construction of the messages and fields. There are four different CAN data/remote frames (see Figure 2-2): • CAN Base Frame: ...

DS70005340A-page 6  2018 Microchip Technology Inc. Figure 2-2: Arbitration Field Figure 2-3: Control Field Figure 2-4: ISO CRC Field ARBITRATION (12/32b) SID<10:0> RTR SID<10:0> RRS SID11 EID<28:18> SRR IDE EID<17:0> RTR EID<28:18> SRR IDE EID<17:0> RRS CAN Base CAN FD Base CAN Ext. CAN FD Ext. CTRL (6/8/9b) IDE FDF I ...

DS70005340A-page 7 CAN FD Protocol Module Figure 2-5: NON-ISO CRC Field Figure 2-6: Error and Overload Frame CRC (16/18/22b) CRC (15b) CRC (15b) CAN Base CAN FD Base CAN Ext. CAN FD Ext. CRC CRC (17/21b) CRC (17/21b) DEL CRC DEL CRC DEL CRC DEL ANYWHERE WITHIN DATA FRAME ERRFLAG (6b) ERRDEL (8b) IFS (= 3b) or OVL EOF or ERR ...

DS70005340A-page 8  2018 Microchip Technology Inc. 2.1.1 DLC ENCODING The Data Length Code (DLC) specifies the number of data bytes a message frame contains. Table 2-1 illustrates the encoding. Table 2-1: DLC Encoding Frame DLC Number of Data Bytes CAN 2.0 and CAN FD 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 CAN 2.0 9-15 8 ...

DS70005340A-page 9 CAN FD Protocol Module 3.0 CONTROL REGISTERS CAN FD operations are controlled using the following Special Function Registers (SFRs). The following registers are described later in this section: • Register 3-1: C1CONH • Register 3-2: C1CONL • Register 3-3: C1NBTCFGH • Register 3-4: C1NBTCFGL • Re ...

DS70005340A-page 10  2018 Microchip Technology Inc. Register 3-1: C1CONH: CAN Control Register High R/W-0 R/W-0 R/W-0 R/W-0 S/HC-0 R/W-1 R/W-0 R/W-0 TXBWS3 TXBWS2 TXBWS1 TXBWS0 ABAT REQOP2 REQOP1 REQOP0 bit 15 bit 8 R-1 R-0 R-0 R/W-1 R/W-1 R/W-0 R/W-0 R/W-0 OPMOD2 OPMOD1 OPMOD1 TXQEN(1) STEF(1) SERRLOM(1) ESIGM(1) RTX ...