DMA Control Registers 5–0 (DCR[5–0])
4
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DSP56303 User’s Manual
4.7
DMA Control Registers 5–0 (DCR[5–0])
The DMA Control Registers (DCR[5–0]) are read/write registers that control the DMA
operation for each of their respective channels. All DCR bits are cleared during processor
reset.
Figure 4-9. DMA Control Register (DCR)
1–0
BAT[1–0]
0
Bus Access Type
Read/write bits that define the type of external memory (DRAM or SRAM) to access for
the area defined by the BAC[11–0],BYEN, BXEN, and BPEN bits. The encoding of
BAT[1–0] is:
00 = Reserved
01 = SRAM access
10 = DRAM access
11 = Reserved
When the external access type is defined as a DRAM access (BAT[1–0] = 10), AA/RAS
acts as a Row Address Strobe (RAS) signal. Otherwise, it acts as an Address Attribute
signal. External accesses to the default area always execute as if BAT[1–0] = 01 (that is,
SRAM access). If Port A is used for external accesses, the BAT bits in the AAR3–0
registers must be initialized to the SRAM access type (that is, BAT = 01) or to the DRAM
access type (that is BAT = 10). To ensure proper operation of Port A, this initialization
must occur even for an AAR register that is not used during any Port A access. Note that
at reset, the BAT bits are initialized to 00.
Table 4-11. DMA Control Register (DCR) Bit Definitions
Bit
Number
Bit Name
Reset
Value
Description
23 DE
0
DMA Channel Enable
Enables the channel operation. Setting DE either triggers a single block DMA transfer in the
DMA transfer mode that uses DE as a trigger or enables a single-block, single-line, or
single-word DMA transfer in the transfer modes that use a requesting device as a trigger. DE
is cleared by the end of DMA transfer in some of the transfer modes defined by the DTM bits.
If software explicitly clears DE during a DMA operation, the channel operation stops only
after the current DMA transfer completes (that is, the current word is stored into the
destination).
Table 4-10. Address Attribute Registers (AAR[0–3]) Bit Definitions
Bit
Number
Bit Name
Reset
Value
Description
23
22
21
20
19
18
17
16
15
14
13
12
DE
DIE
DTM2
DTM1
DTM0
DPR1
DPR0
DCON
DRS4
DRS3
DRS2
DRS1
11
10
9
8
7
6
5
4
3
2
1
0
DRS0
D3D
DAM5
DAM4
DAM3
DAM2
DAM1
DAM0
DDS1
DDS0
DSS1
DSS0
Содержание DSP56303
Страница 1: ...DSP56303 User s Manual 24 Bit Digital Signal Processor DSP56303UM AD Revision 1 January 2001 ...
Страница 52: ...JTAG OnCE Interface 2 22 DSP56303 User s Manual ...
Страница 114: ...General Purpose Input Output GPIO 5 10 DSP56303 User s Manual ...
Страница 212: ...GPIO Signals and Registers 8 26 DSP56303 User s Manual ...
Страница 268: ...Interrupt Equates A 22 DSP56303 User s Manual ...
Страница 306: ...Programming Sheets B 38 DSP56303 User s Manual ...
Страница 320: ...Index 14 DSP56303 User s Manual ...