CCCR

Name:: CCCR
Offset:: 0x18
Reset:: 0x00000001
Access:: Read-only, Write-restricted

Bit31	30	29	28	27	26	25	24

Access
Reset
Bit23	22	21	20	19	18	17	16

Access
Reset
Bit15	14	13	12	11	10	9	8
	TXP	EFBI	PXHD			BRSE	FDOE
Access	R/W	R/W	R/W			R/W	R/W
Reset	0	0	0			0	0
Bit7	6	5	4	3	2	1	0
TEST	DAR	MON	CSR	CSA	ASM	CCE	INIT
AccessR/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset0	0	0	0	0	0	0	1

Bit 14 – TXP: Transmit Pause

Transmit Pause

This bit field is write-restricted and only writable if bit fields CCE = 1 and INIT = 1.

Value	Description
0	Transmit pause disabled.
1	Transmit pause enabled. The CAN pauses for two CAN bit times before starting the next transmission after itself has successfully transmitted a frame.

Bit 13 – EFBI: Edge Filtering during Bus Integration

Edge Filtering during Bus Integration

Value	Description
0	Edge filtering is disabled.
1	Two consecutive dominant tq required to detect an edge for hard synchronization.

Bit 12 – PXHD: Protocol Exception Handling Disable

Protocol Exception Handling Disable

Note: When protocol exception handling is disabled, the CAN will transmit an error frame when it detects a protocol exception condition.

Value	Description
0	Protocol exception handling enabled.
1	Protocol exception handling disabled.

Bit 9 – BRSE: Bit Rate Switch Enable

Bit Rate Switch Enable

Note: When CAN FD operation is disabled FDOE = 0, BRSE is not evaluated.

Value	Description
0	Bit rate switching for transmissions disabled.
1	Bit rate switching for transmissions enabled.

Bit 8 – FDOE: FD Operation Enable

FD Operation Enable

Value	Description
0	FD operation disabled.
1	FD operation enabled.

Bit 7 – TEST: Test Mode Enable

Test Mode Enable

This bit field is write-restricted.

Writing a 0 to this field is always allowed.

Writing a 1 to this field is only allowed if bit fields CCE = 1 and INIT = 1.

Value	Description
0	Normal operation. Register TEST holds reset values.
1	Test Mode, write access to register TEST enabled.

Bit 6 – DAR: Disable Automatic Retransmission

Disable Automatic Retransmission

This bit field is write-restricted and only writable if bit fields CCE = 1 and INIT = 1.

Value	Description
0	Automatic retransmission of messages not transmitted successfully enabled.
1	Automatic retransmission disabled.

Bit 5 – MON: Bus Monitoring Mode

Bus Monitoring Mode

This bit field is write-restricted.

Writing a 0 to this field is always allowed.

Writing a 1 to this field is only allowed if bit fields CCE = 1 and INIT = 1.

Value	Description
0	Bus Monitoring Mode is disabled.
1	Bus Monitoring Mode is enabled.

Bit 4 – CSR: Clock Stop Request

Clock Stop Request

Value	Description
0	No clock stop is requested.
1	Clock stop requested. When clock stop is requested, first INIT and then CSA will be set after all pending transfer requests have been completed and the CAN bus reached idle.

Bit 3 – CSA: Clock Stop Acknowledge

Clock Stop Acknowledge

Value	Description
0	No clock stop acknowledged.
1	CAN may be set in power down by stopping CLK_CAN_APB and GCLK_CAN.

Bit 2 – ASM: Restricted Operation Mode

Restricted Operation Mode

This bit field is write-restricted.

Writing a 0 to this field is always allowed.

Writing a 1 to this field is only allowed if bit fields CCE = 1 and INIT = 1.

Value	Description
0	Normal CAN operation.
1	Restricted Operation Mode active.

Bit 1 – CCE: Configuration Change Enable

Configuration Change Enable

This bit field is write-restricted and only writable if bit field INIT = 1.

Value	Description
0	The CPU has no write access to the protected configuration registers.
1	The CPU has write access to the protected configuration registers (while CCCR.INIT = 1).

Bit 0 – INIT: Initialization

Initialization

Due to the synchronization mechanism between the two clock domains, there may be a delay until the value written to INIT can be read back. The programmer has to assure that the previous value written to INIT has been accepted by reading INIT before setting INIT to a new value.

Value	Description
0	Normal Operation.
1	Initialization is started.