Motorola PowerQUICC II MPC8280 Series Reference Manual page 703

Table 19-10. IDMA BD Field Descriptions (continued)
Offset Bits Name
6 CM
7-8 —
9 SDN
10 DDN
11 DGBL
12-13 DBO
14 —
15 DDTB
0x02 0-1 —
2 SGBL
3-4 SBO
5 —
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Freescale Semiconductor, Inc.
Continuous mode
0 Buffer chaining mode. The CP clears V after this BD is serviced. Buffer chaining
mode is used to transfer large quantities of data into non-contiguous buffer areas.
The user can initialize BDs ahead of time, if needed. The CP automatically loads the
IDMA registers from the next BD values when the transfer is terminated.
1 Auto buffer mode (continuous mode). The CP does not clear V after this BD is
serviced. This is the only difference between auto buffer mode and buffer chaining
mode. Auto buffer mode transfers multiple groups of data to/from a buffer table and
does not require BD reprogramming. The CP automatically reloads the IDMA
registers from the next BD values when the transfer is terminated. Either a single BD
or multiple BDs can be used to create an infinite loop of repeated data moves.
Note: The I bit can still be used to generate an interrupt in this mode.
Reserved, should be cleared.
Source done
0 DONE is inactive during this BD.
1 The IDMA asserts DONE at the last read data phase of the BD.
In fly-by mode (DCM[FB] = 1), SDN should be same as DDN.
Destination done
0 DONE is inactive during this BD.
1 The IDMA asserts DONE at the last write data phase of the BD.
In fly-by mode (DCM[FB] = 1), DDN should be same as SDN.
Destination global
0 Snooping is not activated.
1 Snooping is activated for write transactions to the destination.
In fly-by mode, should be the same as SGBL.
Destination byte ordering:
01 Munged little Endian.
1x Big endian (Motorola).
00 Reserved
In fly-by mode, should be the same as SBO.
Reserved, should be cleared.
Destination data bus.
0 The destination address lies within the 60x bus.
1 The destination address lies within the local bus.
In fly-by mode, should be the same as SDTB.
Reserved, should be cleared.
Source global
0 Snooping is not activated.
1 Snooping is activated for read transactions from the source.
In fly-by mode, should be the same as DGBL.
Source byte ordering:
01 Munged little endian
1x Big endian (Motorola)
00 Reserved
In fly-by mode, should be the same as DBO.
Reserved, should be cleared.
Chapter 19. SDMA Channels and IDMA Emulation
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Description
IDMA Operation
19-27