CONTROLLER AREA NETWORK (bxCAN)
CONTROLLER AREA NETWORK (Cont’d)
CAN MASTER STATUS REGISTER (CMSR)
Reset Value: 0000 0010 (02h)
cleared. Please refer to the AWUM bit of the
CMCR register description for detailed information
for clearing SLEEP bit.
7
0
Bit 0 = INAK Initialization Acknowledge
- Read
0
0
REC TRAN WKUI ERRI SLAK INAK
This bit is set by hardware and indicates to the
software that the CAN hardware is now in initiali-
zation mode. This bit acknowledges the initializa-
tion request from the software (set INRQ bit in
CMCR register).
Note: To clear a bit of this register the software
must write this bit with a one.
This bit is cleared by hardware when the CAN
hardware has left the initialization mode and is
now synchronized on the CAN bus. To be syn-
chronized the hardware has to monitor a se-
quence of 11 consecutive recessive bits on the
CAN RX signal.
Bit 7:4 = Reserved. Forced to 0 by hardware.
Bit 5 = REC Receive
- Read
The CAN hardware is currently receiver.
CAN TRANSMIT STATUS REGISTER (CTSR)
Read / Write
Reset Value: 0000 0000 (00h)
Bit 4 = TRAN Transmit
- Read
The CAN hardware is currently transmitter.
7
0
0
Bit 3 = WKUI Wake-Up Interrupt
- Read/Clear
TXOK2 TXOK1 TXOK0
0
RQCP2 RQCP1 RQCP0
This bit is set by hardware to signal that a SOF bit
has been detected while the CAN hardware was in
sleep mode. Setting this bit generates a status
change interrupt if the WKUIE bit in the CIER reg-
ister is set.
Note: To clear a bit of this register the software
must write this bit with a one.
Bit 7 = Reserved. Forced to 0 by hardware.
This bit is cleared by software.
Bit 2 = ERRI Error Interrupt
Bit 6 = TXOK2 Transmission OK for mailbox 2
- Read
This bit is set by hardware when the transmission
request on mailbox 2 has been completed suc-
cessfully. Please refer to Figure 147.
- Read/Clear
This bit is set by hardware when a bit of the CESR
has been set on error detection and the corre-
sponding interrupt in the CEIER is enabled. Set-
ting this bit generates a status change interrupt if
the ERRIE bit in the CIER register is set.
This bit is cleared by hardware when mailbox 2 is
requested for transmission or when the software
clears the RQCP2 bit.
This bit is cleared by software.
Bit 1 = SLAK Sleep Acknowledge
- Read
This bit is set by hardware and indicates to the
software that the CAN hardware is now in sleep
mode. This bit acknowledges the sleep mode re-
quest from the software (set SLEEP bit in CMCR
register).
Bit 5 = TXOK1 Transmission OK for mailbox 1
- Read
This bit is set by hardware when the transmission
request on mailbox 1 has been completed suc-
cessfully. Please refer to Figure 147.
This bit is cleared by hardware when mailbox 1 is
requested for transmission or when the software
clears the RQCP1 bit.
This bit is cleared by hardware when the CAN
hardware has left sleep mode. Sleep mode is left
when the SLEEP bit in the CMCR register is
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STMICROELECTRONICS [ ST ]
