23-8
MCF5272 User’s Manual
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
AC Electrical Specifications
PRELIMINAR
Y
NOTE:
Above 48 MHz, the memory bus may need to be configured for
one wait state. It is the responsibility of the user to determine
the actual frequency at which to insert a wait state since this
depends on the access time of SRAM or SDRAM used in a
particular system implementation.
Wait states are inserted for SRAM accesses by programming
bits 6–2 of the chip select option registers.
A wait state is added for SDRAM read accesses by setting bit
4 of the SDRAM control register.
Read/write SRAM bus timings listed in Table 23-8 are shown in Figure 23-3, Figure 23-4,
Figure 23-5, and Figure 23-6.
Table 23-8. Processor Bus Output Timing Specifications
Name
Characteristic
1
1
All timing references to SDCLK are given to its rising edge when bit 3 of the SDRAM control register is 0.
0–66 MHz
Unit
Min
Max
Control Outputs
B6a
SDCLK to chip selects (CS[6:0]) valid
—
11
nS
B6b
SDCLK to byte enables (BS[3:0]) valid
—
8.5
nS
B6c
SDCLK to output enable (OE) valid
—
8.5
nS
B6d
SDCLK to write enable (R/W) valid
—
8
nS
B6e
SDCLK to reset output (RSTO) valid
—
7.4
nS
B7a
SDCLK to control output (CS[6:0], OE) invalid (output hold)
2
—
nS
B7b
SDCLK to control output (BS[3:0], R/W) invalid (output hold)
1.5
—
nS
B7c
SDCLK to reset output (RSTO) invalid (output hold)
4
—
nS
Address and Attribute Outputs
B8
SDCLK to address (A[22:0]) valid
—
8.5
nS
B9
SDCLK to address (A[22:0]) invalid (output hold)
2.5
—
nS
Data Outputs
B11
SDCLK to data output (D[31:0]) valid
—
11
nS
B12
2
2
Data output is held valid for one CPU clock period after deassertion of BS[3:0]
SDCLK to data output (D[31:0]) invalid (output hold)
1
—
nS
B13
SDCLK to data output (D[31:0]) high impedance
—
6
nS
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 ...