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Chapter 14 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 633
14.3.2.9 MSCAN Transmitter Message Abort Request Register (CANTARQ)
The CANTARQ register allows abort request of queued messages as described below.
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
Module Base + 0x0008
76543210
R00000
ABTRQ2 ABTRQ1 ABTRQ0
W
Reset: 00000000
= Unimplemented
Figure 14-11. MSCAN Transmitter Message Abort Request Register (CANTARQ)
Table 14-14. CANTARQ Register Field Descriptions
Field Description
2:0
ABTRQ[2:0]
Abort Request — The CPU sets the ABTRQx bit to request that a scheduled message buffer (TXEx = 0) be
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 14.3.2.7, “MSCAN Transmitter Flag Register (CANTFLG)”) and abort acknowledge flags (ABTAK, see
Section 14.3.2.10, “MSCAN Transmitter Message Abort Acknowledge Register (CANTAAK)”) are set and a
transmit interrupt occurs if enabled. The CPU cannot reset ABTRQx. ABTRQx is reset whenever the associated
TXE flag is set.
0 No abort request
1 Abort request pending