MSCAN08 Controller (MSCAN08)
Programmer’s Model of Control Registers
MC68HC08AZ32A — Rev 1.0
Technical Data
MOTOROLA
MSCAN08 Controller (MSCAN08)
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365
20.14.7 MSCAN08 Transmitter Flag Register
The Abort Acknowledge flags are read only. The Transmitter Buffer
Empty flags are read and clear only. A flag can be cleared by writing a 1
to the corresponding bit position. Writing a 0 has no effect on the flag
setting. The Transmitter Buffer Empty flags each have an associated
interrupt enable bit in the CTCR register. A hard or soft reset will resets
the register.
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. The ABTAKx flag is cleared
implicitly whenever the corresponding TXE flag is cleared.
1 = The message has been aborted.
0 = The message has not been aborted, thus has been sent out.
TXE2–TXE0 — Transmitter 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 MSCAN08 sets the
flag after the message has been sent successfully. The flag is also set
by the MSCAN08 when the transmission request was successfully
Address:
$0506
5
Bit 7
6
5
4
3
2
1
Bit 0
Read:
0
ABTAK2
ABTAK1
ABTAK0
0
TXE2
TXE1
TXE0
Write:
Reset:
0
0
0
0
0
1
1
1
= Unimplemented
Figure 20-21. Transmitter Flag Register (CTFLG)
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