AT32F425
Series Reference Manual
2022.03.30
Page 331
Ver 2.01
hardware will automatically leave bus-off mode as soon as
an exit timing is detected on the CAN bus.
When Automatic exit bus-off mode is disabled, the
software must enter/leave the freeze mode once more,
and then the bus-off state is left only when an exit timing is
detected on the CAN bus.
Bit 5
AEDEN
0x0
rw
Automatic exit doze mode enable
0: Automatic exit sleep mode disabled
1: Automatic exit sleep mode enabled
Note:
When
Automatic exit sleep mode is disabled, the sleep
mode is left by software clearing the sleep request
command.
When Automatic exit sleep mode is enabled, the sleep
mode is left without the need of software intervention as
soon as a message is monitored on the CAN bus.
Bit 4
PRSFEN
0x0
rw
Prohibit retransmission enable when sending fails enable
0: Retransmission is enabled.
1: Retransmission is disabled.
Bit 3
MDRSEL
0x0
rw
Message discard rule select when overflow
0: The previous message is discarded.
1: The new incoming message is discarded.
Bit 2
MMSSR
0x0
rw
Multiple message transmit sequence rule
0: The message with the smallest identifier is first
transmitted.
1: The message with the first request order is first
transmitted.
Bit 1
DZEN
0x1
rw
Doze mode enable
0: Sleep mode is disabled.
1: Sleep mode is enabled.
Note:
The hardware will automatically leave sleep mode when
the AEDEN ib set and a message is monitored on the CAN
bus.
After CAN reset or partial software reset, this bit is forced
to be set by hardware, that is, the CAN will keep in sleep
mode, by default.
Bit 0
FZEN
0x0
rw
Freeze mode enable
0: Freeze mode disabled
1: Freeze mode enabled
Note:
The CAN leaves Freeze mode once 11 consecutive
recessive bits have been detected on the RX pin. For this
reason, the software acknowledges the entry of Freeze
mode after the FZC bit is cleared by hardware.
The Freeze mode is entered only when the current CAN
activity (transmission or reception) is completed. Thus the
sotware acknowledges the exit of Freeze mode after the
FZC bit is cleared by hardware.
19.7.1.2 CAN master status register (CAN_MSTS)
Bit
Register
Reset value
Type
Description
Bit 31: 12 Reserved
0x00000
resd
Kept at its default value.
Bit 11
REALRX
0x1
ro
Real time level on RX pin
0: Low
1: High
Bit 10
LSAMPRX
0x1
ro
Last sample level on RX pin
)
0: Low
1: High
。
Note: This value keeps updating with the REALRX.
Bit 9
CURS
0x0
ro
Current receive status
0: No reception occurs
1: Reception is in progress
Note: This bit is set by hardware when the CAN reception