AN2283 Freescale Semiconductor / Motorola, AN2283 Datasheet - Page 14

• Manufacturer Part Number: AN2283
• Description: Scalable Controller Area Network (MSCAN)
• Manufacturer: Freescale Semiconductor / Motorola

AN2283/D
14
NOTE:
Motorola Scalable Controller Area Network (MSCAN) Interrupts
In the CTCR register there are the ABTRQ2, ABTRQ1, and ABTRQ0 bits which
are the Abort Request bits corresponding to the three transmit buffers
respectively. The user will need to set the appropriate ABTRQx bit to abort the
message in the corresponding transmit buffer.
A message currently transmitting on the bus CANNOT be aborted unless an
error or loss of arbitration occurs during transmission.
ABTAK2–ABTAK0 — Abort Acknowledge
TXE2–TXE0 — Transmit Buffer Empty
ABTRQ2–ABTRQ0 — Abort Request
TXEIE2–TXEIE0 — Transmitter Empty Interrupt Enable
This flag acknowledges that a message in the corresponding buffer has
been aborted from transmission due to a pending abort request from the
user. After a particular message buffer has been flagged empty (TXE2,
TXE1, TXE0 = 1), this flag can be used by the application software to identify
whether or not the message has been aborted successfully.
See
The user sets this bit to request that an already scheduled message buffer
(TXE = 0 = buffer is full) be aborted. MSCAN will grant the request when the
message is not already under transmission. When a message is aborted,
the associated TXE and the Abort Acknowledge Flag (ABTAK) will be set
and a TXE interrupt will occur if enabled.
See
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Bit 7
Bit 7
0
0
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1 (set) = The message has been aborted
0 (clear) = The message has not been aborted, message was sent
1 (set) =
0 (clear) = No abort request
Transmission Process
Transmission Process
Figure 10. MSCAN Transmitter Control Register (CTCR)
Figure 9. MSCAN Transmitter Flag Register (CTFLG))
ABTRQ2
ABTAK2
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6
6
successfully
Abort request is pending
ABTRQ1
ABTAK1
5
5
ABTRQ0
ABTAK0
Overview.
Overview.
4
4
3
0
3
0
TXEIE2
TXE2
2
2
TXEIE1
TXE1
1
1
MOTOROLA
TXEIE0
TXE0
Bit 0
Bit 0