MOTOROLA
Chapter 18. SDMA Channels and IDMA Emulation
18-15
Part IV. Communications Processor Module
allocation and eliminates the need for core intervention between transfers. BDs contain
information describing the data block and special control options for the DMA operation
while transferring the data block.
18.8.1 Auto Buffer and Buffer Chaining
The core processor should initialize the IDMA BD table with the appropriate buffer
handling mode, source address, destination address, and block length. See Figure 18-7.
Figure 18-7. IDMA
x
ChannelÕs BD Table
Data associated with each IDMA channel is stored in buffers and each buffer is referenced
by a BD that uses a circular table structure in the dual-port RAM. Control options such as
interrupt and DONE assertion are also programmed on a per-buffer basis in each BD.
Data may be transferred in the two following modes:
¥
Auto buffer mode. The IDMA continuously transfers data to/from the location
programmed in the BD until a
STOP
_
IDMA
command is issued or DONE is asserted
externally.
¥
Buffer chaining mode. Data is transferred according to the Þrst BD parameters, then
the second BD and so forth. The Þrst BD is reused (if ready) until the BD with the
last bit set is reached. IDMA transfers stop and restarts when the BD table is
reinitialized and a
START
_
IDMA
command is issued.
IDMAx 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
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Summary of Contents for MPC8260 PowerQUICC II
Page 1: ...MPC8260UM D 4 1999 Rev 0 MPC8260 PowerQUICC II UserÕs Manual ª ª ...
Page 66: ...lxvi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA ...
Page 88: ...1 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 120: ...2 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 138: ...Part II iv MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II Configuration and Reset ...
Page 184: ...4 46 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II ConÞguration and Reset ...
Page 202: ...Part III vi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 266: ...8 34 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 382: ...10 106 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 392: ...11 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 430: ...Part IV viii MOTOROLA Part IV Communications Processor Module ...
Page 490: ...14 36 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 524: ...17 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
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Page 920: ...31 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 980: ...A 4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Appendixes ...
Page 1002: ...Index 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA INDEX ...
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