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DEMO9S08DZ60
Chapter 12 Freescale’s Controller Area Network (S08MSCANV1)
MC9S08DZ60 Series Data Sheet, Rev. 4
234
Freescale Semiconductor
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).
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
Write: Anytime when not in initialization mode
12.3.8
MSCAN Transmitter Message Abort Request Register (CANTARQ)
The CANTARQ register allows abort request of messages queued for transmission.
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).
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
Write: Anytime when not in initialization mode
Table 12-12. CANTIER Register Field Descriptions
Field
Description
2:0
TXEIE[2:0]
Transmitter Empty Interrupt Enable
0 No interrupt request is generated from this event.
1 A transmitter empty (transmit buffer available for transmission) event causes a transmitter empty interrupt
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. See
” for details.
7
6
5
4
3
2
1
0
R
0
0
0
0
0
ABTRQ2
ABTRQ1
ABTRQ0
W
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 12-12. MSCAN Transmitter Message Abort Request Register (CANTARQ)
Table 12-13. 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
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
”) and abort acknowledge flags (ABTAK, see
”) 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
is set.
0 No abort request
1 Abort request pending