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32180 Group User’s Manual (Rev.1.0)
CAN MODULE
13.5 Transmitting Data Frames
13.5 Transmitting Data Frames
13.5.1 Data Frame Transmit Procedure
The following describes the procedure for transmitting data frames.
(1) Initializing the CAN Message Slot Control Register
Initialize the CAN Message Slot Control Register for the slot to be transmitted by writing H’00 to the register.
(2) Confirming that transmission is idle
Read the CAN Message Slot Control Register that has just been initialized and check the TRSTAT (Transmit/
Receive Status) bit to see that transmission/reception has stopped and remains idle. If this bit = "1", it means
that the CAN module is accessing the message slot. Therefore, wait until the bit is cleared to "0".
(3) Setting transmit data
Set the transmit ID and transmit data in the message slot.
(4) Setting the Extended ID Register
Set the corresponding bit in the Extended ID Register to "0" if the data is to be transmitted as a standard
frame, or "1" if the data is to be transmitted as an extended frame.
(5) Setting the CAN Message Slot Control Register
Write H’80 Note 1 to the CAN Message Slot Control Register to set the TR (Transmit Request) bit to "1".
Note 1: Always be sure to write H’80 when transmitting data frames.
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