mcf5282 Freescale Semiconductor, Inc, mcf5282 Datasheet - Page 229

• Manufacturer Part Number: mcf5282
• Manufacturer: Freescale Semiconductor, Inc

Table 13-3
Freescale Semiconductor
S0
S1
S2
S3
S4
State
describes the states as they appear in subsequent timing diagrams.
All
All
Fast
Termination
Read/write
(skipped fast
termination)
Write
Read/write
(skipped for
fast
termination)
Read
All
Read
(including
fast-terminati
on)
Cycle
High
Low
High
Low
High
CLKOUT
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3
Figure 13-4. Data Transfer State Transition Diagram
Next Cycle
S5
S4
The read or write cycle is initiated in S0. On the rising edge of CLKOUT, the device
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 processor asserts TIP,
SIZ[1:0], and TS on the rising edge of CLKOUT.
The appropriate CSn, BS, and OE signals assert on the CLKOUT falling edge.
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.
TS is negated on the rising edge of CLKOUT in S2.
The data bus is driven out of high impedance as data is placed on the bus on the
rising edge of CLKOUT.
The processor waits for TA assertion. If TA is not sampled as asserted before the
rising edge of CLKOUT at the end of the first clock cycle, the processor inserts wait
states (full clock cycles) until TA is sampled as asserted.
Data is made available by the external device on the falling edge of CLKOUT and
is sampled on the rising edge of CLKOUT with TA asserted.
The external device should negate TA.
The external device can stop driving data after the rising edge of CLKOUT.
However data could be driven through the end of S5.
Table 13-3. Bus Cycle States
Termination
Fast
S0
S3
Wait
States
Description
S1
S2
Basic
Read/Write
External Interface Module (EIM)
13-5