SLAAEN5 February   2025 MSPM0G1106 , MSPM0G1107 , MSPM0G1506 , MSPM0G1507 , MSPM0G1518 , MSPM0G1519 , MSPM0G3106 , MSPM0G3106-Q1 , MSPM0G3107 , MSPM0G3107-Q1 , MSPM0G3506 , MSPM0G3506-Q1 , MSPM0G3507 , MSPM0G3507-Q1 , MSPM0G3518 , MSPM0G3518-Q1 , MSPM0G3519 , MSPM0G3519-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Bridge between CAN and SPI
  5. 2Implementation
    1. 2.1 Principle
    2. 2.2 Structure
  6. 3Software Description
    1. 3.1 Software Functionality
    2. 3.2 Configurable Parameters
    3. 3.3 Structure of Custom Element
    4. 3.4 Structure of FIFO
    5. 3.5 SPI Receive and Transmit (Transparent Transmission)
    6. 3.6 SPI Receive and Transmit (Protocol Transmission)
    7. 3.7 CAN Receive and Transmit
    8. 3.8 Application Integration
  7. 4Hardware
  8. 5Application Aspects
    1. 5.1 Flexible structure
    2. 5.2 Optional Configuration for SPI
    3. 5.3 Optional Configuration for CAN
    4. 5.4 CAN Bus Multinode Communication Example
  9. 6Summary
  10. 7References

3.2 Configurable Parameters

All the configurable parameters are defined in user_define.h, which are listed in Table 3-3.

For SPI, both transparent transmission and protocol transmission are supported in this example, switching by defining SPI_TRANSPARENT or SPI_PROTOCOL.

In transparent transmission, users can configure the timeout for the SPI slave to detect one SPI message receiving done. Users can also configure the default data length(SPI_TRANSPARENT_LENGTH) for the message from the SPI slave to the SPI master. Table 3-2 lists the number of bytes for receiving or sending with different modes.

In protocol transmission, users can configure the ID length for different formats. Note that there is a fixed 2-byte header(0x55 0xAA) and one byte of data-length. To modify the format more, users can modify the code directly.

#define SPI_TRANSPARENT
#ifdef SPI_TRANSPARENT
/* The format of SPI:
     * Transparent transmission - Data1 Data2 ...*/
/* data length for SPI master receiving or SPI slave transmitting*/
#define SPI_TRANSPARENT_LENGTH  (8)     //need be <= TRANSMIT_DATA_LENGTH
#define SPI_TIMEOUT     (0x4000)      //timeout 250ms
#else
/* The format of SPI:
     * if SPI_ID_LENGTH = 4, format is 55 AA ID1 ID2 ID3 ID4 Length Data1 Data2 ...
     * if SPI_ID_LENGTH = 1, format is 55 AA ID Length Data1 Data2 ...
     * if SPI_ID_LENGTH = 0, format is 55 AA Length Data1 Data2 ...*/
//#define SPI_ID_LENGTH  (0)
//#define SPI_ID_LENGTH  (1)
#define SPI_ID_LENGTH  (4)
#endif
Table 3-2 Number of Bytes for Receiving or Sending with Different SPI Modes
Parameter SPI Interface: Master SPI Interface: Slave
How many bytes are received? How many bytes are sent? How many bytes are received? How many bytes are sent?
Protocol Transmission (2+SPI_ID_LENGT+1+Length) bytes (2+SPI_ID_LENGT+1+Length) bytes (2+SPI_ID_LENGT+1+Length) bytes (2+SPI_ID_LENGT+1+Length) bytes
Transparent Transmission (SPI_TRANSPARENT_LENGTH) bytes (Length) bytes Timeout identify the end of message (SPI_TRANSPARENT_LENGTH) bytes

For CAN, ID or data length are included in CAN frame. Users can add another ID in the data area by changing the CAN_ID_LENGTH (Default value is 0).

/* The format of CAN:
     * if CAN_ID_LENGTH = 4, format is ID1 ID2 ID3 ID4 Data1 Data2 ...
     * if CAN_ID_LENGTH = 1, format is ID Data1 Data2 ...
     * if CAN_ID_LENGTH = 0, format is Data1 Data2 ...*/
#define CAN_ID_LENGTH  (0)
//#define CAN_ID_LENGTH  (1)
//#define CAN_ID_LENGTH  (4)

Table 3-3 Configurable Parameters
Parameter Optional value Description
#define SPI_TRANSPARENT Define / Not define Enables the SPI transparent transmission.
#define SPI_PROTOCOL Define / Not define Enables the SPI protocol transmission.
#defineSPI_TRANSPARENT_LENGTH (8) The default data length for message from the SPI slave to the SPI master. Only available when SPI_TRANSPARENT is defined. In this case, default value is eight bytes.
#define SPI_TIMEOUT (0x4000) Timeout = SPI_TIMEOUT / 32768 s Timeout to indicate one SPI message receiving done.Only available when SPI_TRANSPARENT is defined. In this case, default value is 250ms.
#define SPI_ID_LENGTH (4) 0/1/4 Optional SPI ID length, which is related to the ID area in protocol. Only available when SPI_PROTOCOL is defined. In this case, default value is four bytes.
#define CAN_ID_LENGTH (0) 0/1/4 Optional CAN ID length, which is related to the ID area in protocol. In this case, the default value is 0 byte
#define TRANSMIT_DATA_LENGTH (12) <=64 Size of data area. If the received message contains more data than this value, it can result in data loss
#define C2S_FIFO_SIZE (8) Size of CAN to SPI FIFO. Note the usage of SRAM.
#define S2C_FIFO_SIZE (8) Size of SPI to CAN FIFO. Note the usage of SRAM.
#define DEFAULT_SPI_ORIGIN_ID (0x00) Default value for SPI origin ID
#define DEFAULT_SPI_DESTINATION_ID (0x00) Default value for SPI destination ID
#define DEFAULT_CAN_ORIGIN_ID (0x00) Default value for CAN origin ID
#define DEFAULT_CAN_DESTINATION_ID (0x00) Default value for CAN destination ID