LSI Symbios SYM53C040, Technical Manual

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Microcontroller Interface Timings 9-9
9.4 Microcontroller Interface Timings
This section provides timing information for the microcontroller interface.
The AC characteristics described in this section apply over the entire
range of operating conditions for the SYM53C040.
9.4.1 External Memory Interface
Figure 9.5 External Memory Interface Waveforms
Table 9.14 External Memory Interface Timings
Symbol Parameter Min Max Units
T
1
ALE pulse width = duration of positive ALE pulse 23 – ns
T
2
PSEN/ pulse width = duration of negative PSEN/ pulse 75 – ns
T
3
PSEN/ falling to instruction valid = maximum delay from
PSEN/ falling to input data valid – 55 ns
T
4
Data hold to PSEN/ rising = minimum hold time for data
after PSEN/ rises 0 – ns
T
5
ALE falling to instruction valid = maximum delay from ALE
falling to input data valid – 80 ns
T
6
Address valid to ALE falling = minimum setup time for
A[15:8] and AD[7:0] to ALE falling 20 – ns
ALE
t
4
t
3
t
1
PSEN/
AD[7:0]
A[15:8]
A[7:0]
ADDR INSTR ADDR INSTR
t
2
t
6
t
5
ADDR ADDR
ADDR ADDR