mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 424

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

Memory Map and Registers
424
START
SMOD
DMOD
DSIZE
18–17
15–12
11–8
Field
16
Controls whether the destination address increments after each successful transfer.
0
1
Destination size
Determines the data size of the destination bus cycle for the DMA controller.
00
01
10
11
Start transfer
0
1
Source address modulo
Defines the size of the source data circular buffer used by the DMA Controller. If enabled (SMOD is non-
zero), the buffer base address is located on a boundary of the buffer size. The value of this boundary is
based upon the initial source address (SAR). The base address should be aligned to a 0-modulo-(circular
buffer size) boundary. Misaligned buffers are not possible. The boundary is forced to the value
determined by the upper address bits in the field selection.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Destination address modulo
Defines the size of the destination data circular buffer used by the DMA Controller. If enabled (DMOD
value is non-zero), the buffer base address is located on a boundary of the buffer size. The value of this
boundary depends on the initial destination address (DAR). The base address should be aligned to a 0-
modulo-(circular buffer size) boundary. Misaligned buffers are not possible. The boundary is forced to the
value determined by the upper address bits in the field selection.
No change to the DAR after a successful transfer.
The DAR increments by 1, 2, 4 depending upon the size of the transfer.
DMA inactive
The DMA begins the transfer in accordance to the values in the TCDn. START is cleared
automatically after one module clock and always reads as logic 0.
Longword
Byte
Word
Reserved (generates a configuration error (DSRn[CE]) if incorrectly specified at time of channel
activation)
Buffer disabled
Circular buffer size is 16 bytes
Circular buffer size is 32 bytes
Circular buffer size is 64 bytes
Circular buffer size is 128 bytes
Circular buffer size is 256 bytes
Circular buffer size is 512 bytes
Circular buffer size is 1 KB
Circular buffer size is 2 KB
Circular buffer size is 4 KB
Circular buffer size is 8 KB
Circular buffer size is 16 KB
Circular buffer size is 32 KB
Circular buffer size is 64 KB
Circular buffer size is 128 KB
Circular buffer size is 256 KB
DMA_DCRn field descriptions (continued)
MCF51JF128 Reference Manual, Rev. 2, 03/2011
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Preliminary
Description
Freescale Semiconductor, Inc.