Commell MPX-2515 Manual do Utilizador descarregar pdf (Página 13)

Commell MPX-2515 User’s Guide Rev 0100

Taiwan Commate Computer Inc.

It is possible to write to sequential registers by continuing to clock in data bytes, as

long as CS# is held low. Data will actually be written to the register on the rising

edge of the SCK line for the D0 bit. If the CS# line is brought high before eight bits

are loaded, the write will be aborted for that data byte and previous bytes in the

command will have been written. The following figure shows the timing diagram of

the byte write sequence.

Figure 3 MCP2515 Write Instruction

#define CCP_CAN_SYSTEM_SERVICE 0X20 /* COMMAND: command code */

#define CAN_WRITE_INSTRUCT 0X88 /* DATA_0: sub-command code */

#define EP2 2 /* Endpoint 2 */

#define EP3 3 /* Endpoint 3 */

OFFSET BULK OUT (EP2) BULK IN (EP1)

SIZEOF_DATA ?? 0X01

COMMAND 0X20 0X20

ERROR 0X00 Error code

DATA_0 0X88 Number of bytes written

DATA_1 Number of bytes to write Checksum

DATA_2 0X02 (constant)

DATA_3 Starting register address

DATA_4 Byte_0

DATA_5 Byte_1

DATA_6 Byte_2

... ...

DATA_N Checksum

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 37 38

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