
DMA Programming Model
MOTOROLA
DMA Controller Module
14-9
Note: Only part of the on-chip SRAM can be accessed by the DMA. The memory
controlled by RAMBAR0 is not visible for DMA. The memory controlled by
RAMBAR1 is visible for DMA. As a result, the SAR or DAR address range cannot
be programmed to on-chip SRAM0 memory, since the on-chip DMAs cannot
access on-chip SRAM0 as a source or destination. They can access SRAM1,
however.
14.4.3
FLASHMEDIA DATA REGISTERS
The destination address register (DAR) is a 32-bit register containing the address to which the DMA
controller module sends data during a transfer.
Note: The MCF5249 on-chip DMAs must be careful when transferring data to cacheable
memory since the on-chip DMAs do not maintain cache coherency with the
MCF5249 instruction cache.
14.4.4
BYTE COUNT REGISTER
The byte count register (BCR) is a 24-bit register containing the number of bytes remaining to be
transferred for a given block. The offset within the memory map is based on the value of the BCR24BIT bit
in the MPARK register of the SIM module. See the following table for the bit locations.
Note: If the BCR24BIT = 1, the upper 8 bits are loaded with zeros.
The BCR decrements on the successful completion of the address phase of a write transfer in
dual-address mode. The amount the BCR decrements is 1, 2, 4, or 16 for byte, word, longword, or line
accesses, respectively.
RESET
00
000
00
0
R/W
MBAR + $300), MBAR+ $340, MBAR + $380, MBAR + $3C0)
Table 14-14 Destination Address Register (DAR)
BITS
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FIELD
DAR3
1
DAR3
0
DAR2
9
DAR2
8
DAR2
7
DAR2
6
DAR2
5
DAR2
4
DAR2
3
DAR2
2
DAR2
1
DAR2
0
DAR1
9
DAR1
8
DAR1
7
DAR1
6
RESET0
00
0
R/W
BITS
15
14
13
12
11
10
98
765
43
21
0
FIELD
DAR1
5
DAR1
4
DAR1
3
DAR1
2
DAR1
1
DAR1
0
DAR9 DAR8 DAR7 DAR6 DAR5 DAR4 DAR3 DAR2 DAR1 DAR0
RESET0
00
0
R/W
MBAR + $304, MBAR + $344, MBAR + $384, MBAR + $3C4
Table 14-13 Source Address Register (SAR) (Continued)
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Freescale Semiconductor, Inc.
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