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(transmitter or receiver) is running the transparent protocol, the other half (receiver or
transmitter) can support another protocol. In such a case, use the PSMR for the
non-transparent protocol.
29.10 SCC Transparent Receive Buffer Descriptor
(RxBD)
The CPM reports information about the received data for each buffer using an RxBD,
closes the current buffer, generates a maskable interrupt, and starts receiving data into the
next buffer after one of the following occurs:
¥ An error is detected.
¥ A full receive buffer is detected.
¥ An
ENTER HUNT MODE
¥ A
CLOSE RXBD
0
1
Offset + 0
E
Ñ
Offset + 2
Offset + 4
Offset + 6
Figure 29-2. SCC Transparent Receive Buffer Descriptor (RxBD)
Table 29-7 describes RxBD status and control Þelds.
Table 29-7. SCC Transparent RxBD Status and Control Field Descriptions
Bits Name
0
E
Empty.
0 The buffer is full or stopped receiving data because an error occurred. The core can read or write to
any Þelds of this RxBD. The CPM does not use this BD when RxBD[E] is zero.
1 The buffer is not full. This RxBD and buffer are owned by the CPM. Once E is set, the core should
not write any Þelds of this RxBD.
1
Ñ
Reserved, should be cleared.
2
W
Wrap (Þnal BD in table).
0 Not the last BD in the table.
1 Last BD in the table. After this buffer is used, the CPM receives data into the Þrst BD that RBASE
points to. The number of BDs in this table is determined only by RxBD[W] and overall space
constraints of the dual-port RAM.
3
I
Interrupt.
0 No interrupt is generated after this buffer is used.
1 When this buffer is closed by the transparent controller, the SCCE[RXB] is set. SCCE[RXB] can
cause an interrupt if it is enabled.
MOTOROLA
command is Issued.
command is issued.
2
3
4
5
W
I
L
F
CM
Chapter 29. SCC Transparent Mode
Part V. The Communications Processor Module
6
7
8
9
10
Ñ
DE
Ñ
Data Length
Rx Buffer Pointer
Description
11
12
13
14
NO
Ñ
CR
OV
CD
29-9
15
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