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SDRAM Controller
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
9-4
Freescale Semiconductor
shows how BS[3:0] should be connected to DQM
x
for 16- and 32-bit SDRAM configurations.
9.3
Interface to SDRAM Devices
The following tables describes possible memory configurations using most common SDRAM devices for
16- and 32-bit wide data buses.
A device’s data bus width affects its connection to SDRAM address pins. A device can be configured for
external data bus width of 16 or 32 bits by appropriate configuration of the WSEL signal during reset. See
Section 19.18, “Operating Mode Configuration Pins
.” The following tables describe address pin
connections and internal address multiplexing.
Table 9-2. Connecting BS[3:0] to DQM
x
5272
SDRAM
Data Signals
16 Bit
32 Bit
16 Bit
32 Bit (2 x 16)
32 Bit (1 x 32)
BS3
BS3
DQMH
DQMH
DQM3
D[31:24]
BS2
BS2
DQML
DQML
DQM2
D[23:16]
NC
BS1
NC
DQMH
DQM1
D[15:8]
NC
BS0
NC
DQML
DQM0
D[7:0]
Table 9-3. Configurations for 16-Bit Data Bus
Parameter
8-Bit
16-Bit
16 Mbits
64 Mbits
16 Mbits
64 Mbits
128 Mbits
256 Mbits
Number of devices
2
1
Total size
4 Mbytes
16 Mbytes
2 Mbytes
8 Mbytes
16 Mbytes
32 Mbytes
Total page size
1 Kbyte
1 Kbyte
512 Kbytes 512 Kbytes
1 Kbyte
1 Kbyte
Number of banks
2
4
2
4
4
4
Refresh count in 64 mS
4K
4K
4K
4K
4K
8K
Table 9-4. Configurations for 32-Bit Data Bus
Parameter
8-Bit
16-Bit
32-Bit
16 Mbits
64Mbits
16 Mbits
64 Mbits
128 Mbits
256 Mbits
64 Mbits
128 Mbits
Number of devices
4
2
1
Total size
8 Mbytes
32 Mbytes
4 Mbytes
16 Mbytes
32 Mbytes
64 Mbytes
8 Mbytes
16 Mbytes
Total page size
2 Kbytes
2 Kbytes
1 Kbyte
1 Kbyte
2 Kbytes
2 Kbytes
1 Kbyte
1 Kbyte
Number of banks
2
4
2
4
4
4
4
4
Refresh count in 64 mS
4K
4K
4K
4K
4K
8K
4K
8K