Chapter 20. Bus Operation
20-15
External Bus Interface Types
20.6.2 Interface for FLASH/SRAM Devices without Byte
Strobes
CSBRn[EBI] is 11 for FLASH/SRAM devices and for peripherals having 8-bit data bus
widths and no byte strobe inputs. These type of memory devices have separate pins for
write enable, chip select, and output enable. All chip selects support this EBI mode.
The key difference between EBI = 11 and EBI = 00 is that BS[3:0] can be directly
connected to the R/W inputs of the 8-bit wide SRAM devices and the R/W output from the
MCF5272 can be left unconnected.
The number of wait states required for the external memory or peripheral can be
programmed in CSORn[WS]. The external transfer acknowledge signal, TA, is provided to
allow off-chip control of wait states. External control of wait states is enabled when
CSORn[WS] is 0x1F.
Figure 20-10. Longword Read; EBI=11; 32-Bit Port; Internal Termination
CLKIN
A[22:0]
D[31:0]
OE
R/W
CSn
BS[3:0]
TA
C1
C2
(H)
(H)
(H)
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...