Freescale Semiconductor MPC8260 - Manual (Page 670)

SDMA Channels and IDMA Emulation
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
19-26 Freescale Semiconductor
6 CM 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.
7-8 — Reserved, should be cleared.
9 SDN 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.
10 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.
11 DGBL 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.
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.
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.
0x02 0-1 — Reserved, should be cleared.
2 SGBL 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.
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.
Table 19-10. IDMA BD Field Descriptions (continued)
Offset Bits Name Description