MSC8144E Reference Manual, Rev. 3
14-42
Freescale
Semiconductor
Direct Memory Access (DMA) Controller
14.6.21 DMA Channel Buffer Descriptors
Figure 14-13 shows a diagram of the BD pointer scheme.
Figure 14-13. Buffer Descriptor Pointers
Following are the actual addresses of the source and destination BDs for any channel:
BDT_BASE = DMABDBR[BDT_PTR]
×
256
Source BD = BD DMACHCR[SRCBDPT]
×
16
×
(DMACHCR[SMDC] + 1)
Destination BD: BD CHCR[DMADESBDPT]
×
16
×
(DMACHCR[DMDC] + 1)
Offset is the decoded value of DMABDBR[DESO]
The VCOP channel BDs are located in memory outside the VCOP. Each channel has a BD table
to hold the BDs for both source and destination buffers. All BDs of all channels must be located
in memory connected to MBus interface 0. Figure 14-14 shows the structure of one-dimensional
BD, which is a 128-bit entry.
Figure 14-14. DMA Channel BD One-Dimensional Line
BDT_PTR
DESO
DES_BDPT
DMABDBRx
DMACHCRx
BD
BD
SRC_BDPT
{
Note: Memory location can be M2, M3, or DDR.
127
BD_ADDR
BD_SIZE
BD_ATTR
BD_BSIZE
32 Bits
32 Bits
32 Bits
32 Bits
0
32
64
96
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...