SDMA Channels and IDMA Emulation
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
19-26 Freescale Semiconductor
6CM 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.
1Auto 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.
7-8 Reserved, should be cleared.
9SDN Source done
0DONE
is inactive during this BD.
1The 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.
10 DDN Destination done
0DONE
is inactive during this BD.
1The 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.
11 DGBL Destination global
0Snooping is not activated.
1Snooping is activated for write transactions to the destination.
In fly-by mode, should be the same as SGBL.
12-13 DBO Destination byte ordering:
01 Munged little Endian.
1x Big endian (Freescale).
00 Reserved
In fly-by mode, should be the same as SBO.
14 Reserved, should be cleared.
15 DDTB Destination data bus.
0The destination address lies within the 60x bus.
1The destination address lies within the local bus.
In fly-by mode, should be the same as SDTB.
0x02 0-1 Reserved, should be cleared.
2SGBL Source global
0Snooping is not activated.
1Snooping is activated for read transactions from the source.
In fly-by mode, should be the same as DGBL.
3-4 SBO Source byte ordering:
01 Munged little endian
1x Big endian (Freescale)
00 Reserved
In fly-by mode, should be the same as DBO.
5 Reserved, should be cleared.
Table19-10. IDMA BD F ield Descriptions (continued)
Offset Bits Name Description