Data Sheet

MCP2515
DS21801D-page 18 Preliminary © 2005 Microchip Technology Inc.
REGISTER 3-1: TXBnCTRL – TRANSMIT BUFFER n CONTROL REGISTER
(ADDRESS: 30h, 40h, 50h)
U-0 R-0 R-0 R-0 R/W-0 U-0 R/W-0 R/W-0
— ABTF MLOA TXERR TXREQ — TXP1 TXP0
bit 7 bit 0
bit 7 Unimplemented: Read as ‘0’
bit 6 ABTF: Message Aborted Flag bit
1 = Message was aborted
0 = Message completed transmission successfully
bit 5 MLOA: Message Lost Arbitration bit
1 = Message lost arbitration while being sent
0 = Message did not lose arbitration while being sent
bit 4 TXERR: Transmission Error Detected bit
1 = A bus error occurred while the message was being transmitted
0 = No bus error occurred while the message was being transmitted
bit 3 TXREQ: Message Transmit Request bit
1 = Buffer is currently pending transmission
(MCU sets this bit to request message be transmitted - bit is automatically cleared when
the message is sent)
0 = Buffer is not currently pending transmission
(MCU can clear this bit to request a message abort)
bit 2 Unimplemented: Read as ‘0’
bit 1-0 TXP: Transmit Buffer Priority <1:0> bits
11 = Highest Message Priority
10 = High Intermediate Message Priority
11 = Low Intermediate Message Priority
00 = Lowest Message Priority
Legend:
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