MOTOROLA
Chapter 13. External Interface Module (EIM)
13-5
Data Transfer Operation
3. The last clock of the bus cycle uses what would be an idle clock between cycles to
provide hold time for address, attributes and write data. Figure 13-6 and Figure 13-8
show the basic read and write operations.
13.4.2 Data Transfer Cycle States
The data transfer operation in the MCF5282 is controlled by an on-chip state machine. Each
bus clock cycle is divided into two states. Even states occur when CLKOUT is high and
odd states occur when CLKOUT is low. The state transition diagram for basic and fast
termination read and write cycles are shown in Figure 13-4.
Figure 13-4. Data Transfer State Transition Diagram
Table 13-3 describes the states as they appear in subsequent timing diagrams.
Table 13-3. Bus Cycle States
State
Cycle
CLKOUT
Description
S0
All
High
The read or write cycle is initiated in S0. On the rising edge of CLKOUT, the
MCF5282 places a valid address on the address bus and drives R/W high for a
read and low for a write, if it is not already in the appropriate state. The MCF5282
asserts TIP, SIZ[1:0], and TS on the rising edge of CLKOUT.
S1
All
Low
The appropriate CS
n
, BS, and OE signals assert on the CLKOUT falling edge.
Fast
Termination
TA must be asserted during S1. Data is made available by the external device
and is sampled on the rising edge of CLKOUT with TA asserted.
S2
Read/write
(skipped fast
termination)
High
TS is negated on the rising edge of CLKOUT in S2.
Write
The data bus is driven out of high impedance as data is placed on the bus on the
rising edge of CLKOUT.
S0
S3
S5
S4
S1
S2
Basic
Next Cycle
Wait
States
Read/Write
Fast
Termination
Summary of Contents for ColdFire MCF5281
Page 124: ...3 20 MCF5282 User s Manual MOTOROLA EMAC Instruction Set Summary ...
Page 141: ...MOTOROLA Chapter 5 Static RAM SRAM 5 5 SRAM Programming Model ...
Page 142: ...5 6 MCF5282 User s Manual MOTOROLA SRAM Programming Model ...
Page 168: ...6 26 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 186: ...7 18 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 228: ...9 22 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 246: ...10 18 MCF5282 User s Manual MOTOROLA Low Power Wakeup Operation ...
Page 254: ...11 8 MCF5282 User s Manual MOTOROLA Memory Map and Registers ...
Page 264: ...12 10 MCF5282 User s Manual MOTOROLA Chip Select Registers ...
Page 280: ...13 16 MCF5282 User s Manual MOTOROLA Misaligned Operands ...
Page 314: ...14 34 MCF5282 User s Manual MOTOROLA MCF5282 External Signals ...
Page 339: ...MOTOROLA Chapter 15 Synchronous DRAM Controller Module 15 25 SDRAM Example ...
Page 340: ...15 26 MCF5282 User s Manual MOTOROLA SDRAM Example ...
Page 356: ...16 16 MCF5282 User s Manual MOTOROLA DMA Controller Module Functional Description ...
Page 408: ...17 52 MCF5282 User s Manual MOTOROLA Buffer Descriptors ...
Page 446: ...20 24 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 474: ...22 18 MCF5282 User s Manual MOTOROLA Programming Model ...
Page 510: ...23 36 MCF5282 User s Manual MOTOROLA Operation ...
Page 526: ...24 16 MCF5282 User s Manual MOTOROLA I2C Programming Examples ...
Page 672: ...28 12 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 718: ...29 46 MCF5282 User s Manual MOTOROLA Motorola Recommended BDM Pinout ...
Page 750: ...32 8 MCF5282 User s Manual MOTOROLA Ordering Information ...