mcf5272 Freescale Semiconductor, Inc, mcf5272 Datasheet - Page 462

• Manufacturer Part Number: mcf5272
• Description: Mcf5272 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

External Bus Interface Types
20.6 External Bus Interface Types
The MCF5272 supports three types of external bus interfaces. The interface type is
programmed using CSBRn[EBI]. The EBI codes are summarized in Table 20-7.
20.6.1 Interface for FLASH/SRAM Devices with Byte Strobes
CSBRn[EBI] is 00 for FLASH/SRAM devices and peripherals having 16- or 32-bit data
20-8
SRAM/ROM
SRAM/ROM
16-/32-bit
Reserved
SDRAM
8-bit
A0
Transfer Size A[1:0]
Byte
Word
Longword
Line
CSBRn[EBI] Applicable Chip Select
Table 20-6. Data Bus Requirement for Read/Write Cycles
00
01
10
11
Table 20-7. External Bus Interface Codes for CSBRs
00
01
10
11
00
01
10
11
00
01
10
11
00
01
10
11
D[31:24] D[23:16] D[15:8]
CS7/SDCS only
Byte 0
Byte 0
Byte 0
Byte 0
—
—
—
—
—
—
—
—
X
X
X
X
All
—
All
MCF5272 User’s Manual
Byte 1
Byte 1
Byte 1
Byte 1
32-Bit Port
—
—
—
—
—
—
—
—
X
X
X
X
External Data Bytes Required
Byte 2
Byte 2
Byte 2
For 16/32 bit wide memory devices with byte strobe inputs.
BS[3:0]
CSBR0[EBI] = 00 at reset.
One physical bank of SDRAM consisting of 16–256 Mbit
devices. The CS7/SDCS CSORn[WS] must be set to 0x1F.
—
SRAM/ROM timing for 8 bit wide memory devices without
byte strobe inputs.
this mode.
Byte2
—
—
—
—
—
—
—
—
X
X
X
X
are byte read/write enables in this mode.
D[7:0]
Byte 3
Byte 3
Byte 3
Byte 3
—
—
—
—
—
—
—
—
X
X
X
X
D[31:24] D[23:16]
BS[3:0]
Byte 0
Byte 2
Byte 0
Byte 2
Byte 0
Byte 2
Byte 0
Byte 2
—
—
—
—
—
—
X
X
16-Bit Port
function as byte write enables in
Note
Byte 1
Byte 3
Byte 1
Byte 3
Byte 1
Byte 3
Byte 1
Byte 3
—
—
—
—
—
—
X
X
8-Bit Port
D[31:24]
Byte 0
Byte 1
Byte 2
Byte 3
Byte 0
Byte 1
Byte 2
Byte 3
Byte 0
Byte 1
Byte 2
Byte 3
Byte 0
Byte 1
Byte 2
Byte 3
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