AN2283 Freescale Semiconductor / Motorola, AN2283 Datasheet - Page 10

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

AN2283/D
Transmission
Process
10
NOTE:
Motorola Scalable Controller Area Network (MSCAN) Interrupts
The MSCAN Transmitter Flag Register (CTFLG) and the MSCAN Transmitter
Control Register (CTCR) are relevant to the transmit process on the MSCAN.
See
This CTFLG register is a special one. ABTAK2–ABTAK0 are status bits;
however, TXE2–TXE0 are status as well as control bits.
ABTAK2–ABTAK0 — Abort Acknowledge
TXE2–TXE0 — Transmit Buffer Empty
ABTRQ2–ABTRQ0 — Abort Request
TXEIE2–TXEIE0 — Transmitter Empty Interrupt Enable
See
This flag indicates that the associated transmit message buffer is empty;
therefore, not scheduled for transmission. It is cleared by the user writing a 1
(using the exclusive-OR operation: 1
loaded in the transmit buffer and is due for transmission. The MSCAN will
set this flag after the message has been sent successfully, or when a
message set up for transmission in a buffer is successfully aborted due to
an abort request (see
See
The user sets these bits while the buffer is filled. When the associated
transmit buffers are empty (TXEx = 1) after a successful transmission, the
interrupt occurs indicating a message can be loaded into that empty buffer.
Freescale Semiconductor, Inc.
Bit 7
Bit 7
0
0
Figure 7
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1 (set) =
0 (clear) = The associated message buffer is filled and is scheduled for
1 (set) =
0 (clear) = No interrupt will be generated when the corresponding
Abort Process
Abort Process
Figure 8. MSCAN Transmitter Control Register (CTCR)
Figure 7. MSCAN Transmitter Flag Register (CTFLG)
ABTRQ2
ABTAK2
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and
6
6
The associated message buffer is empty (not scheduled).
transmission.
When the corresponding transmit buffer is emptied it will
result in a transmitter empty interrupt.
transmit buffer is empty.
Figure
ABTRQ1
ABTAK1
Overview.
Overview.
5
5
Abort Process
8.
ABTRQ0
ABTAK0
4
4
Overview).
1 = 0) when a message has been
3
0
3
0
TXEIE2
TXE2
2
2
TXEIE1
TXE1
1
1
MOTOROLA
TXEIE0
TXE0
Bit 0
Bit 0