38.13.22 CxFIFOCONy

CAN FIFO y Control Register

Note:

The individual bytes in this multibyte register can be accessed with the following register names:
- CxFIFOCONyT: Accesses the top byte FIFOCONy[31:24]
- CxFIFOCONyU: Accesses the upper byte FIFOCONy[23:16]
- CxFIFOCONyH: Accesses the high byte FIFOCONy[15:8]
- CxFIFOCONyL: Accesses the low byte FIFOCONy[7:0]
[y] denotes FIFO number, from 1 to 3.
These bits can only be modified in Configuration mode (OPMOD[2:0] = 100).

Name:	CxFIFOCONy
Offset:	0x00


Bit	31	30	29	28	27	26	25	24
	PLSIZE[2:0]			FSIZE[4:0]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0


Bit	23	22	21	20	19	18	17	16
		TXAT[1:0]		TXPRI[4:0]
Access		R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset		1	1	0	0	0	0	0


Bit	15	14	13	12	11	10	9	8
						FRESET	TXREQ	UINC
Access						S/HC	R/W/HC	S/HC
Reset						1	0	0


Bit	7	6	5	4	3	2	1	0
	TXEN	RTREN	RXTSEN	TXATIE	RXOVIE	TFERFFIE	TFHRFHIE	TFNRFNIE
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0

Bits 31:29 – PLSIZE[2:0] Payload Size⁽³⁾

Value	Description
111	64 data bytes
110	48 data bytes
101	32 data bytes
100	24 data bytes
011	20 data bytes
010	16 data bytes
001	12 data bytes
000	8 data bytes

Bits 28:24 – FSIZE[4:0] FIFO Size⁽³⁾

Bits 22:21 – TXAT[1:0] Retransmission Attempts

This feature is enabled when RTXAT (CxCON[16]) is set.

Value	Description
11	Unlimited number of retransmission attempts
10	Unlimited number of retransmission attempts
01	Three retransmission attempts
00	Disables retransmission attempts

Bits 20:16 – TXPRI[4:0] Message Transmit Priority

Value	Description
11111	Highest message priority
00000	Lowest message priority

Bit 10 – FRESET FIFO Reset

Value	Description
1	FIFO will be reset when bit is set, cleared by hardware whenever FIFO is reset, user needs to poll whether this bit is clear before taking any action
0	No effect

Bit 9 – TXREQ Message Send Request

Value	Name	Description
1	TXEN = `1` (FIFO configured as a transmit FIFO)	Requests sending a message; the bit will automatically clear when all the messages queued in the FIFO are successfully sent
0	TXEN = `1` (FIFO configured as a transmit FIFO)	Clearing the bit to ‘`0`’ while set (‘`1`’) will request a message abort
x	TXEN = `0` (FIFO configured as a receive FIFO)	This bit has no effect

Bit 8 – UINC Increment Head/Tail

Value	Name	Description
1	TXEN = `1` (FIFO configured as a transmit FIFO)	When this bit is set, the FIFO head will increment by a single message
1	TXEN = `0` (FIFO configured as a receive FIFO)	When this bit is set, the FIFO tail will increment by a single message

Bit 7 – TXEN TX/RX Buffer Selection

Value	Description
1	Transmits message object
0	Receives message object

Bit 6 – RTREN Auto-Remove Transmit (RTR) Enable

Value	Description
1	When a Remote Transmit is received, TXREQ will be set
0	When a Remote Transmit is received, TXREQ will be unaffected

Bit 5 – RXTSEN Received Message Timestamp Enable⁽³⁾

Value	Description
1	Captures timestamp in a received message object in RAM
0	Does not capture time stamp

Bit 4 – TXATIE Transmit Attempts Exhausted Interrupt Enable

Value	Description
1	Enables interrupt
0	Disables interrupt

Bit 3 – RXOVIE Overflow Interrupt Enable

Value	Description
1	Interrupt is enabled for overflow event
0	Interrupt is disabled for overflow event

Bit 2 – TFERFFIE Transmit/Receive FIFO Empty/Full Interrupt Enable

Value	Name	Description
1	TXEN = `1` (FIFO configured as a transmit FIFO)	Interrupt is enabled for FIFO empty
0	TXEN = `1` (FIFO configured as a transmit FIFO)	Interrupt is disabled for FIFO empty
1	TXEN = `0` (FIFO configured as a receive FIFO)	Interrupt is enabled for FIFO full
0	TXEN = `0` (FIFO configured as a receive FIFO)	Interrupt is disabled for FIFO full

Bit 1 – TFHRFHIE Transmit/Receive FIFO Half Empty/Half Full Interrupt Enable

Value	Name	Description
1	TXEN = `1` (FIFO configured as a transmit FIFO)	Interrupt is enabled for FIFO half empty
0	TXEN = `1` (FIFO configured as a transmit FIFO)	Interrupt is disabled for FIFO half empty
1	TXEN = `0` (FIFO configured as a receive FIFO)	Interrupt is enabled for FIFO half full
0	TXEN = `0` (FIFO configured as a receive FIFO)	Interrupt is disabled for FIFO half full

Bit 0 – TFNRFNIE Transmit/Receive FIFO Not Full/Not Empty Interrupt Enable

Value	Name	Description
1	TXEN = `1` (FIFO configured as a transmit FIFO)	Interrupt is enabled for FIFO not full
0	TXEN = `1` (FIFO configured as a transmit FIFO)	Interrupt is disabled for FIFO not full
1	TXEN = `0` (FIFO configured as a receive FIFO)	Interrupt is enabled for FIFO not empty
0	TXEN = `0` (FIFO configured as a receive FIFO)	Interrupt is disabled for FIFO not empty

The individual bytes in this multibyte register can be accessed with the following register names: CxFIFOCONyT: Accesses the top byte FIFOCONy[31:24] CxFIFOCONyU: Accesses the upper byte FIFOCONy[23:16] CxFIFOCONyH: Accesses the high byte FIFOCONy[15:8] CxFIFOCONyL: Accesses the low byte FIFOCONy[7:0] [y] denotes FIFO number, from 1 to 3. These bits can only be modified in Configuration mode (OPMOD[2:0] = 100).