MC912DG128ACPVE Datasheet, PDF (360/478 Pages) Freescale Semiconductor, Inc – Upward compatible with M68HC11 instruction set

Freescale Semiconductor, Inc.
MSCAN Controller
18.13.8 msCAN12 Transmitter Flag Register (CTFLG)
The Abort Acknowledge flags are read only. The Transmitter Buffer
Empty flags are read and clear only. A flag can be cleared by writing a1
to the corresponding bit position. Writing a zero has no effect on the flag
setting. The Transmitter Buffer Empty flags each have an associated
interrupt enable flag in the CTCR register. A hard or soft reset will reset
the register.
Bit 7
6
5
4
3
CTFLG R
0
ABTAK2 ABTAK1 ABTAK0
0
$0106 W
RESET
0
0
0
0
0
2
TXE2
1
1
TXE1
1
Bit 0
TXE0
1
ABTAK2 – ABTAK0 — Abort Acknowledge
This flag acknowledges that a message has been aborted due to a
pending abort request from the CPU. After a particular message
buffer has been flagged empty, this flag can be used by the
application software to identify whether the message has been
aborted successfully or has been sent in the meantime. The flag is
reset implicitly whenever the associated TXE flag is set to 0.
0 = The massage has not been aborted, thus has been sent out.
1 = The message has been aborted.
TXE2 – TXE0 —Transmitter Buffer Empty
This flag indicates that the associated transmit message buffer is
empty, thus not scheduled for transmission. The CPU must
handshake (clear) the flag after a message has been set up in the
transmit buffer and is due for transmission. The msCAN12 will set the
flag after the message has been sent successfully. The flag will also
be set by the msCAN12 when the transmission request was
successfully aborted due to a pending abort request (msCAN12
Transmitter Control Register (CTCR)). If not masked, a transmit
interrupt is pending while this flag is set.
Clearing this flag will also clear the corresponding Abort Acknowledge
flag (ABTAK, see above). Setting this flag will clear the corresponding
Abort Request flag (ABTRQ, msCAN12 Transmitter Control Register
(CTCR)).
Technical Data
360
MC68HC912DT128A — Rev 4.0
MSCAN Controller
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