MCF5282CVM66 Datasheet, PDF (305/766 Pages) Freescale Semiconductor, Inc – MCF5282 and MCF5216 ColdFire® Microcontroller User’s Manual

DMA Controller Module
Table 16-3. DCRn Field Descriptions (continued)
Bits Name
Description
27–25
BWC
Bandwidth control. Indicates the number of bytes in a block transfer. When the byte count reaches a
multiple of the BWC value, the DMA releases the bus. For example, if BCR24BIT is 0, BWC is 001
(512 bytes or value of 0x0200), and BCR is 0x1000, the bus is relinquished after BCR values of
0x0E00, 0x0C00, 0x0A00, 0x0800, 0x0600, 0x0400, and 0x0200. If BCR24BIT is 0, BWC is 110, and
BCR is 33000, the bus is released after 232 bytes because the BCR is at 32768, a multiple of 16384.
Encoding
000
001
010
011
100
101
110
111
BCR24BIT = 0
BCR24BIT = 1
DMA has priority and does not negate its
request until transfer completes.
512
16384
1024
32768
2048
65536
4096
131072
8192
262144
16384
524288
32768
1048576
24–23 — Reserved, should be cleared.
22 SINC Source increment. Controls whether a source address increments after each successful transfer.
0 No change to SAR after a successful transfer.
1 The SAR increments by 1, 2, 4, or 16, as determined by the transfer size.
21–20
SSIZE
Source size. Determines the data size of the source bus cycle for the DMA control module.
00 Longword
01 Byte
10 Word
11 Line (16-byte burst)
19 DINC Destination increment. Controls whether a destination address increments after each successful
transfer.
0 No change to the DAR after a successful transfer.
1 The DAR increments by 1, 2, 4, or 16, depending upon the size of the transfer.
18–17
DSIZE
Destination size. Determines the data size of the destination bus cycle for the DMA controller.
00 Longword
01 Byte
10 Word
11 Line (16-byte burst)
16 START Start transfer.
0 DMA inactive
1 The DMA begins the transfer in accordance to the values in the control registers. START is cleared
automatically after one system clock and is always read as logic 0.
Freescale Semiconductor
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3
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