COMMELL MPX-2515 User Manual
Page 12
Commell MPX-2515 User’s Guide Rev 0100
Taiwan Commate Computer Inc.
12
register locations can be read sequentially using this method. The read operation is
terminated by raising the CS# pin. The following figure shows the MCP2515 Read
instruction.
Figure 2 MCP2515 Read Instruction
#define CCP_CAN_SYSTEM_SERVICE 0X20 /* COMMAND: command code */
#define CAN_READ_INSTRUCT 0X86 /* DATA_0: sub-command code */
#define EP2 2 /* Endpoint 2 */
#define EP3 3 /* Endpoint 3 */
OFFSET
BULK OUT (EP2)
BULK IN (EP1)
SIZEOF_DATA
0X04
Number of bytes returned
COMMAND
0X20
Byte_0 (return byte 0)
ERROR
0X00
Byte_1 (return byte 1)
DATA_0
0X86
Byte_2 (return byte 2)
DATA_1
Number of bytes to read
...
DATA_2
0X03 (constant)
...
DATA_3
Starting register address
...
DATA_4
Checksum
...
...
DATA_n
Checksum
1.5.7 CAN_WRITE_INSTRUCT
The CAN_WRITE_INSTRUCT implements MCP2515 Write Instruction. The
Write instruction is started by lowering the CS# pin. The Write instruction is then
sent to the MCP2515 followed by the address and at least one byte of data.