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External NOP Cycles and Idle Cycles
In consecutive external bus accesses, in which even if the cycles that access no external space
(external NOP cycles) exist, the condition of inserting idle cycles is effective. In this case, the
external NOP cycles are counted as a part of the idle cycles.
Figure 6.37 shows an example of external NOP and idle cycle insertion.
T
1
Bφ
Address bus
CS (area A)
CS (area B)
RD
Data bus
(Condition: Number of idle cycles to be inserted when different reads continue: 4 cycles)
No external access
Preceding bus cycle
T
T
T
2
pw
3
Specified number of idle cycles or more
including no external access cycles (NOP)
Figure 6.37 Idle Cycle Insertion Example
Idle cycle
(NOP)
(remaining)
T
T
i
i
Rev.2.00 Jun. 28, 2007 Page 203 of 666
Section 6 Bus Controller (BSC)
Following bus cycle
T
T
T
T
1
2
pw
REJ09B0311-0200
3
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