GD32VF103 User Manual
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Loopback communication mode
Loopback communication mode means the sending messages are transferred into the
reception FIFOs, the RX pin is disconnected from the CAN network and the TX pin can send
messages to the CAN network.
Set LCMOD bit in CAN_BT register to enter loopback communication mode or clear it to leave.
Loopback communication mode is useful on self-test.
Loopback and silent communication mode
Loopback and silent communication mode means the RX and TX pins are disconnected from
the CAN network while the sending messages are transferred into the reception FIFOs.
Set LCMOD and SCMOD bit in CAN_BT register to enter loopback and silent communication
mode or clear them to leave.
Loopback and silent communication mode is useful on self-test. The TX pin holds logical one.
The RX pin holds high impedance state.
Normal communication mode
Normal communication mode is the default communication mode unless the LCMOD or
SCMOD bit in CAN_BT register is set.
20.3.3.
Data transmission
Transmission register
Three transmit mailboxes are transparent to the application. You can use transmit mailboxes
through four transmission registers: CAN_TMIx, CAN_TMPx, CAN_TMDATA0x and
Figure 20-2. Transmission register
Figure 20-2. Transmission register
Application
Transmit
mailbox 0
Transmit
mailbox 1
Transmit
mailbox 2
TMI2
TMP2
TMDATA02
TMDATA12
TMI0
TMP0
TMDATA00
TMDATA10
TMI1
TMP1
TMDATA01
TMDATA11