MSC8144E Reference Manual, Rev. 3
14-44
Freescale
Semiconductor
Direct Memory Access (DMA) Controller
14.6.21.1
Buffer Attributes (BD_ATTR)
Table 14-28. One-Dimensional BD Field Descriptions
Bits
Description
BD_ADDR
127–96
Current Buffer Address
Holds the buffer address pointer. This value increments on every transaction the DMA controller issues for
this buffer. If the buffer is cyclic, the original address value is restored when the BD_SIZE value reaches
zero. For details, refer to Section 14.2.2, One-Dimensional Cyclic Buffer, on page 14-4.
BD_SIZE
95–64
Size of Transfer Left for Current Buffer
Contains the remaining size of the buffer. This value decrements by the transfer size each time the DMA
controller issues a transaction until it reaches zero. When BD_SIZE reaches zero, the value is restored to
the value of BD_BSIZE.
Note:
The BD_SIZE must not be programmed as zero. A value of zero sets DMAERR[BDSZ] and
freezes the channel. To reactivate the channel, you must disable the channel, reprogram the
BDs, and reactivate the channel.
BD_ATTR
63–32
Buffer Attributes
This 32-bit parameter describes the attributes of the channel handling this buffer. The fields of the
BD_ATTR parameter are described in Table 14-29.
BD_BSIZE
31–0
Buffer Base Size
Holds the base size of the buffer.
BD_ATTR
Buffer Attributes
Bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SST CYC CONT NPRTNO_INC
—
NBD
Type
R/W
Reset
Undefined
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CNT
PP
TSZ
—
FRZ
MR
—
BTSZ
Type
R/W
Reset
Undefined
Table 14-29. BD_ATTR Field Descriptions
Bits
Description
Settings
SST
31
Set Status
Indicates whether to set the associated status bit in DMASTR
when size reaches zero and the last data transaction ends.
Setting this bit in the destination buffer issues a masked
interrupt request.
0 Do not set status
1 Set
status.
CYC
30
Cyclic Address
Indicates the behavior of BD_ADDR when BD_SIZE reaches
zero. For details on cyclic buffers, see Section 14.2, Buffer
Types, on page 14-2.
0 Sequential address: BD_ADDR increments.
1 Cyclic address: BD_ADDR is restored to the
original value for a one-dimensional buffer.
CONT
29
Continuous Buffer Mode
Indicates whether buffer is to close when BD_SIZE reaches
zero.
0 Buffer
closes.
1 Buffer continues operating.
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 ...