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MC9S12HZ256_08 Datasheet, PDF (349/692 Pages) Freescale Semiconductor, Inc – Microcontrollers | |||
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Chapter 12 Freescaleâs Scalable Controller Area Network (MSCANV2)
12.3.2.9 MSCAN Transmitter Message Abort Request Register (CANTARQ)
The CANTARQ register allows abort request of queued messages as described below.
7
6
5
4
3
2
1
R
0
0
0
0
0
ABTRQ2 ABTRQ1
W
Reset:
0
0
0
0
0
0
0
= Unimplemented
Figure 12-10. MSCAN Transmitter Message Abort Request Register (CANTARQ)
NOTE
The CANTARQ register is held in the reset state when the initialization
mode is active (INITRQ = 1 and INITAK = 1). This register is writable when
not in initialization mode (INITRQ = 0 and INITAK = 0).
Read: Anytime
Write: Anytime when not in initialization mode
0
ABTRQ0
0
Table 12-15. CANTARQ Register Field Descriptions
Field
Description
2:0
Abort Request â The CPU sets the ABTRQx bit to request that a scheduled message buffer (TXEx = 0) be
ABTRQ[2:0] aborted. The MSCAN grants the request if the message has not already started transmission, or if the
transmission is not successful (lost arbitration or error). When a message is aborted, the associated TXE (see
Section 12.3.2.7, âMSCAN Transmitter Flag Register (CANTFLG)â) and abort acknowledge ï¬ags (ABTAK, see
Section 12.3.2.10, âMSCAN Transmitter Message Abort Acknowledge Register (CANTAAK)â) are set and a
transmit interrupt occurs if enabled. The CPU cannot reset ABTRQx. ABTRQx is reset whenever the associated
TXE ï¬ag is set.
0 No abort request
1 Abort request pending
MC9S12HZ256 Data Sheet, Rev. 2.05
Freescale Semiconductor
349
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