COMMELL MPX-2515 - Manual (Page 35)

Commell MPX-2515 User’s Guide Rev 0100
Taiwan Commate Computer Inc. 35
Figure 7 Bit Modify Instruction
The part is selected by lowering the CS# pin and the Bit Modify command byte is
then sent to the MCP2515. The command is followed by the address of the register,
the mask byte and finally the data byte.
The mask byte determines which bits in the register will be allowed to change. A '1'
in the mask byte will allow a bit in the register to change, while a '0' will not.
The data byte determines what value the modified bits in the register will be
changed to. A '1' in the data byte will set the bit and a '0' will clear a bit, provided
that the mask for that bit is set to a '1'.
1.9.2 CAN_BIT_MODIFY Command
The CAN_BIT_MODIFY command is provided to implement the MCP2515 Bit
Modify Instruction.
The following figure defines the MCP2515 Bit Modify Instruction. Please refer to
the MCP2515 data sheet for detail information.