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DMA Controller
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
Freescale Semiconductor
10-3
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 CSCR
n
[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
4–2
SRCT
Source addressing type. Used internal to the MCF5272 to qualify the address bits. The value should be
compatible with the CSCR
n
[TM] value used for external RAM or peripheral device access.
000 Reserved
001 User data access
010 User code access
011 Reserved
100 Reserved
101 Supervisor data access
110 Supervisor code access
111 Reserved
Table 10-2. DMR Field Descriptions (continued)
Bits
Name
Description