MOTOROLA
Chapter 20. SDMA Channels and IDMA Emulation
20-9
Part V. The Communications Processor Module
20.3.3.3 IDMA Mask Registers (IDMR1 and IDMR2)
The read/write IDMA mask registers (IDMR1 and IDMR2) have the same format as IDSR,
shown in Figure 20-6. If an IDMR bit is set, the corresponding interrupt is enabled in
IDSRn; if it is cleared, the corresponding interrupt is masked. Reset clears IDMR.
IDMR1Õs internal address (IMMR offset) is 0x914; IDMR2Õs is 0x91C.
20.3.4 IDMA Buffer Descriptors (BD)
An IDMA buffer descriptor contains the speciÞc transfer information needed for its buffer.
IDMA BDs contain a status-and-control Þeld, the function code registers, the buffer length,
and the source and destination buffer pointers. The BDs are grouped together in contiguous
dual-port RAM to form a standard BD table; see Figure 20-7.
Figure 20-7. IDMAx ChannelÕs BD Table
An IDMA descriptor breaks down as follows:
¥
The half word at ( 0) is the status-and-control Þeld.
¥
The byte at ( 2) is the destination function code register (DFCR). See
Section 20.3.4.1, ÒFunction Code RegistersÑSFCR and DFCR.Ó
6
DONE
Buffer chain done. Indicates IDMA transfer termination. Set after servicing a BD that has its L bit
(last) set, regardless of the I bit setting.
7
OB
Out of buffers. Indicates that the IDMA channel has no valid BDs left in the BD table.
Table 20-6. IDSR1/IDSR2 Field Descriptions (Continued)
Bits Name
Description
IDMA
x
BD Base
Address (IBASE)
Source Device or
Buffer 0
Source Device or
Buffer 1
Source Device or
Buffer 2
Source Device or
Buffer
n
BD 0
Destination Device or
Buffer 0
BD 1
BD 2
BD
n
Destination Device or
Buffer 1
Destination Device or
Buffer 2
Destination Device or
Buffer
n
¥
¥
¥
¥
¥
¥
¥
¥
¥
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 ...
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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 ...
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Page 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
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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 ...
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