MOTOROLA
Chapter 30. Serial Management Controllers
30-17
Part V. The Communications Processor Module
Table 30-9 describes SMC UART TxBD status and control Þelds.
Data length represents the number of octets that the CP should transmit from this BDÕs
buffer. It is never modiÞed by the CP and normally is greater than zero. It can be zero if P
is set, in which case only a preamble is sent. If there are more than 8 bits in the UART
character, data length should be even. For example, to transmit three UART characters of
8-bit data, 1 start, and 1 stop, initialize the data length Þeld to 3. To send three UART
characters of 9-bit data, 1 start, and 1 stop, the data length Þeld should 6, because the three
9-bit data Þelds occupy three half words in memory (the 9 LSBs of each half word).
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0
R
Ñ
W
I
Ñ
CM
P
Ñ
2
Data Length
4
Tx Buffer Pointer
6
Figure 30-8. SMC UART Transmit BD (TxBD)
Table 30-9. SMC UART TxBD Status and Control Field Descriptions
Bits
Name
Description
0
R
Ready
0 The buffer is not ready for transmission; BD and its buffer can be altered. The CP clears R after the
buffer has been sent or an error occurs.
1 The buffer has not been completely sent. This BD must not be updated while R is set.
1
Ñ
Reserved, should be cleared.
2
W
Wrap (Þnal BD in the TxBD table)
0 Not the last BD in the table.
1 Last BD in the table. After this buffer is used, the CP receives incoming data into the Þrst BD that
TBASE points to. The number of TxBDs in this table is determined only by the W bit and overall
space constraints of the dual-port RAM.
3
I
Interrupt
0 No interrupt is generated after this buffer is serviced.
1 The SMCE[TX] is set when this buffer is serviced. TX can cause an interrupt if it is enabled.
4Ð5
Ñ
Reserved, should be cleared.
6
CM
Continuous mode
0 Normal operation.
1 The CP does not clear R after this BD is closed and automatically retransmits the buffer when it
accesses this BD next.
7
P
Preamble
0 No preamble sequence is sent.
1 The UART sends one all-ones character before it sends the data so that the other end detects an
idle line before the data is received. If this bit is set and the data length of this BD is zero, only a
preamble is sent.
8Ð15 Ñ
Reserved, should be cleared.
Summary of Contents for MPC860 PowerQUICC
Page 3: ...MPC860UM AD 07 98 REV 1 MPC860 PowerQUICC ª UserÕs Manual ...
Page 36: ...xxxvi MPC860 PowerQUICC UserÕs Manual MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 78: ...I iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 88: ...1 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 114: ...3 16 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 226: ...8 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 262: ...9 36 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 320: ...12 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 325: ...MOTOROLA Part IV Hardware Interface IV v Part IV Hardware Interface ...
Page 326: ...IV vi MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 352: ...13 26 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
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Page 632: ...21 44 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 660: ...22 28 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
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Page 998: ...37 48 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part VI Debug and Test ...
Page 1016: ...A 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1024: ...B 8 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1030: ...C 6 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
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