Chapter 10. DMA Controller
10-3
DMA Controller Registers
Table 10-2. DMR Field Descriptions
Bits
Name
Description
31
RESET
Reset. Writing a 1 to this location causes the DMA controller to reset to a condition where no
transfers are taking place. EN is cleared, preventing new transfers.
30
EN
Enable. Controls whether the DMA channel is enabled to perform transfers.
0 DMA transfers are disabled.
1 DMA transfers are enabled. The DMA controller can respond to requests from the peripheral or
generates internal requests in dual address mode, so long as the conditions described under
the DMA interrupt flags (see Section 10.3.2, “DMA Interrupt Register (DIR)”) do not prevent
transfers from going ahead.
29–20
—
Reserved, should be cleared.
19–18
RQM
Request mode. Determines the request mode of the channel. This must be 11.
00–10 Reserved, do not use.
11 Dual address request mode. Both the DMA source and DMA destination are memory
addresses. The MCF5272 supports only dual-address request mode.
17–15
—
Reserved, should be cleared.
14–13
DSTM
Destination addressing mode for the channel.
00 Static address mode
01 Increment address mode
1x Reserved, do not use.
12–10
DSTT
Destination addressing type. Used internal to the MCF5272 to qualify the address bits. This value
should be compatible with the CSCRn[TM] value used for external RAM or peripheral device
access.
000 Reserved
001 User data access
010 User code access
011–100 Reserved
101 Supervisor data access
110 Supervisor code access
111 Reserved
9–8
DSTS
Destination data transfer type. The DMA controller buffers data from the source address data
fetches until there are enough bytes to perform a destination data write of the size programmed in
these bits. Thus it is possible to configure source accesses to be byte type and destination
addresses to be line burst type. In this case 16 individual byte reads are performed followed by an
indivisible burst write of four longwords. Longword or line bursts are the most efficient data
transfers.
DSTS
Data Transfer Type
Address Incremented by
00
Longword
4
01
Byte 1
10
Word
2
11
16-byte line burst
16. Valid only for SDRAM.
7
—
Reserved, should be cleared.
6
—
Reserved, should be cleared.
5
SRCM
Source addressing mode of the channel.
0
Static address mode
1
Increment address mode
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
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Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...