UPD78F0838 Renesas Electronics Corporation., UPD78F0838 Datasheet - Page 603

• Manufacturer Part Number: UPD78F0838
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

15.8 CAN Controller Initialization
15.8.1 Initialization of CAN module
CCP[3:0] bits of the C0GMCS register by software. Do not change the setting of the CAN module system clock after
CAN module operation is enabled.
15.8.2 Initialization of message buffer
the message buffers, even for those not used in the application, is necessary before switching the CAN module from
the initialization mode to one of the operation modes.
15.8.3 Redefinition of message buffer
message is being received or transmitted, without affecting other transmission/reception operations.
Before the CAN module operation is enabled, the CAN module system clock needs to be determined by setting the
The CAN module is enabled by setting the GOM bit of the C0GMCTRL register.
For the procedure of initializing the CAN module, refer to 15.16 Operation Of CAN Controller.
After the CAN module is enabled, the message buffers contain undefined values. A minimum initialization for all
- Clear the RDY, TRQ, and DN bits of the C0MCTRLm register to 0.
- Clear the MA0 bit of the C0MCONFm register to 0.
Redefining a message buffer means changing the ID and control information of the message buffer while a
(3) To redefine message buffer during transmission
(1) To redefine message buffer in initialization mode
(2) To redefine message buffer during reception
Remark m = 0 to 15
Place the CAN module in the initialization mode once and then change the ID and control information of the
message buffer in the initialization mode. After changing the ID and control information, set the CAN module
in an operation mode.
Perform redefinition as shown in Figure 15-40. Message Buffer Redefinition.
To rewrite the contents of a transmit message buffer to which a transmission request has been set, perform
transmission abort processing (refer to 15.10.4 (1) Transmission abort process except for in normal
operation mode with automatic block transmission (ABT) and 15.10.4 (2) Transmission abort process
except for ABT transmission in normal operation mode with automatic block transmission (ABT).
Confirm that transmission has been aborted or completed, and then redefine the message buffer. After
redefining the transmit message buffer, set a transmission request using the procedure described below.
When setting a transmission request to a message buffer that has been redefined without aborting the
transmission in progress, however, the 1-bit wait time is not necessary.
Preliminary User’s Manual U19748EJ1V0UD
CHAPTER 15 CAN CONTROLLER
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