20-10
MPC860 PowerQUICC UserÕs Manual
MOTOROLA
Part V. The Communications Processor Module
¥
The byte at ( 3) is the source function code register (SFCR). See
Section 20.3.4.1, ÒFunction Code RegistersÑSFCR and DFCR.Ó
¥
The word at ( 4) is the buffer length, containing the number of bytes for
transfer. It must be greater than zero.
¥
The word at ( 8) points to the beginning of the source buffer in internal or
external memory.
Ñ When the source is a peripheral, this Þeld is ignored in single-address mode. In
dual-address mode, this Þeld contains the peripheral address.
¥
The word at ( 0xC) points to the beginning of the destination buffer in
internal or external memory.
Ñ When the destination is a peripheral, this Þeld is ignored in single-address mode.
In dual-address mode, this Þeld contains the peripheral address.
Figure 20-8 shows the descriptor structure.
Table 20-7 describes an IDMA descriptorÕs status-and-control Þeld.
Offset
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0x00
V
Ñ
W
I
L
Ñ
CM
Ñ
Ñ
Ñ
Ñ
Ñ
Ñ
Ñ
Ñ
Ñ
0x02
DFCR
SFCR
0x04
Buffer Length
0x06
0x08
Source Buffer Pointer
0x0A
0x0C
Destination Buffer Pointer
0x0E
Figure 20-8. IDMA Buffer Descriptor Structure
Table 20-7. IDMA BD Status and Control Bits
Bits
Name
Description
0
V
Valid. Ready for processing.
0 Invalid. Not ready for transfer. The user can write to this descriptor and its buffer. When
buffer-chaining, the CP clears the V bit after the buffer has been transferred.
1 Valid for transfer. The user should not write to this descriptor or its buffer once the V bit is set.
Note: When an error condition is detected, the CP clears the V bit.
1
Ñ
Reserved
2
W
Wrap. Marks the end of the BD table.
0 Not the last descriptor in the BD table.
1 Last descriptor in the BD table. After this descriptor has been processed, the CP wraps the
current BD pointer (IBPTR) back to the top of the BD table (IBASE).
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 ...
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Page 632: ...21 44 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 ...
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