
7-10
MCF5249UM
MOTOROLA
Synchronous Operation
7.3.3
GENERAL SYNCHRONOUS OPERATION GUIDELINES
To reduce system logic and to support a variety of SDRAM sizes, the DRAM controller provides SDRAM
control signals as well as a multiplexed row address and column address to the SDRAM.
When SDRAM blocks are accessed, the DRAM controller can operate in either burst or continuous page
mode. The following sections describe the DRAM controller interface to SDRAM, the supported bus
transfers, and initialization.
7.3.3.1 ADDRESS MULTIPLEXING
Table 7-7 shows the generic address multiplexing scheme for SDRAM configurations. All possible address
connection configurations can be derived from this table.
The following tables provide a more comprehensive, step-by-step way to determine the correct address
line connections for interfacing the MCF5249 to SDRAM. To use the tables, find the one that corresponds
to the number of column address lines on the SDRAM and to the port size as seen by the MCF5249, which
is not necessarily the SDRAM port size. For example, if two 1M x 16-bit SDRAMs together form a
1M x 32-bit memory, the port size is 32 bits. Most SDRAMs likely have fewer address lines than are shown
in the tables, so follow only the connections shown until all SDRAM address lines are connected.
Table 7-7 SDRAM Interface (8-Bit Port,10-Column Address Lines)
MCF5249 Pins
A17
A16
A15
A14
A13
A12
A11
A10
A9
A19
A20
A21
A22
A23
Row
1716151413121110
9
1920212223
Column
012345678
18
SDRAM Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
Table 7-8 SDRAM Interface (8-Bit Port,11-Column Address Lines)
MCF5249 Pins
A17
A16
A15
A14
A13
A12
A11
A10
A9
A19
A21
A22
A23
Row
1716151413121110
9
19212223
Column
01234567
8
18
20
SDRAM Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
Table 7-9 SDRAM Interface (8-Bit Port,12-Column Address Lines)
MCF5249 Pins
A17
A16
A15
A14
A13
A12
A11
A10
A9
A19
A21
A23
Row
1716151413121110
9
192123
Column
01234567
8
18
20
22
SDRAM Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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