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CLKOUT
ARDY
In a Normally-Ready system, a wait state will be inserted when 1 & 2 are met.
(Assumes SRDY is low.)
1.
T
CLIS
2.
T
CLIH
CLKOUT
ARDY
SRDY
Alternatively, in a Normally-Ready system, a wait state will be inserted
when1 & 2 are met for SRDY and ARDY.
1.
T
CHIS
2.
T
CHIH
Failure to meet READY setup and hold can cause a device failure
!
(i.e., the bus hangs or operates inappropriately).
Conditions causing the BIU to become idle include the following.
•
The instruction prefetch queue is full.
•
An effective address calculation is in progress.
•
The bus cycle inherently requires idle states (e.g., interrupt acknowledge, locked opera-
tions).
•
Instruction execution forces idle states (e.g., HLT, WAIT).
T2
2
1
: ARDY low to clock high
: Clock high to ARDY high (ARDY inactive hold time)
T2
1
: ARDY and SRDY low to clock low
: ARDY and SRDY low from clock low
Figure 3-18. Normally Ready System Timings
BUS INTERFACE UNIT
T3
TW
T3
TW
2
T4
T4
A1045-0A
3-19
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