Datasheet

PIC18F66K80 FAMILY
DS39977F-page 400  2010-2012 Microchip Technology Inc.
27.2.2 DEDICATED CAN TRANSMIT
BUFFER REGISTERS
This section describes the dedicated CAN Transmit
Buffer registers and their associated control registers.
REGISTER 27-5: TXBnCON: TRANSMIT BUFFER n CONTROL REGISTERS [0  n  2]
Mode 0
U-0 R-0 R-0 R-0 R/W-0 U-0 R/W-0 R/W-0
TXBIF TXABT
(1)
TXLARB
(1)
TXERR
(1)
TXREQ
(2)
—TXPRI1
(3)
TXPRI0
(3)
Mode 1,2
R/C-0 R-0 R-0 R-0 R/W-0 U-0 R/W-0 R/W-0
TXBIF TXABT
(1)
TXLARB
(1)
TXERR
(1)
TXREQ
(2)
—TXPRI1
(3)
TXPRI0
(3)
bit 7 bit 0
Legend: C = Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7
TXBIF: Transmit Buffer Interrupt Flag bit
1 = Transmit buffer has completed transmission of a message and may be reloaded
0 = Transmit buffer has not completed transmission of a message
bit 6
TXABT: Transmission Aborted Status bit
(1)
1 = Message was aborted
0 = Message was not aborted
bit 5
TXLARB: Transmission Lost Arbitration Status bit
(1)
1 = Message lost arbitration while being sent
0 = Message did not lose arbitration while being sent
bit 4
TXERR: Transmission Error Detected Status bit
(1)
1
= A bus error occurred while the message was being sent
0 = A bus error did not occur while the message was being sent
bit 3
TXREQ: Transmit Request Status bit
(2)
1 = Requests sending a message; clears the TXABT, TXLARB and TXERR bits
0 = Automatically cleared when the message is successfully sent
bit 2
Unimplemented: Read as ‘0’
bit 1-0
TXPRI<1:0>: Transmit Priority bits
(3)
11 = Priority Level 3 (highest priority)
10 = Priority Level 2
01 = Priority Level 1
00 = Priority Level 0 (lowest priority)
Note 1: This bit is automatically cleared when TXREQ is set.
2: While TXREQ is set, Transmit Buffer registers remain read-only. Clearing this bit in software while the bit is
set will request a message abort.
3: These bits define the order in which transmit buffers will be transferred. They do not alter the CAN
message identifier.