Freescale’s Scalable Controller Area Network (S12MSCANV3)
1. Read: Anytime
Write: Anytime when not in initialization mode
NOTE
The CANTIER 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).
Table 8-14. CANTIER Register Field Descriptions
Field
Description
2-0
Transmitter Empty Interrupt Enable
TXEIE[2:0] 0 No interrupt request is generated from this event.
1 A transmitter empty (transmit buffer available for transmission) event causes a transmitter empty interrupt
request.
8.3.2.9
MSCAN Transmitter Message Abort Request Register (CANTARQ)
The CANTARQ register allows abort request of queued messages as described below.
Module Base + 0x0008
Access: User read/write(1)
7
6
5
4
3
2
1
0
R
W
0
0
0
0
0
ABTRQ2
ABTRQ1
ABTRQ0
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 8-12. MSCAN Transmitter Message Abort Request Register (CANTARQ)
1. Read: Anytime
Write: Anytime when not in initialization mode
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).
Table 8-15. CANTARQ Register Field Descriptions
Description
Field
2-0
Abort Request — 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 8.3.2.7, “MSCAN Transmitter Flag Register (CANTFLG)”) and abort acknowledge flags (ABTAK, see
Section 8.3.2.10, “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
S12P-Family Reference Manual, Rev. 1.13
Freescale Semiconductor
267
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