80C251 Intel, 80C251 Datasheet - Page 19

• Manufacturer Part Number: 80C251
• Description: Search -----> N80C251
• Manufacturer: Intel

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Table 11 lists AC timing parameters for the
8XC251SA/SB/SP/SQ with no wait states. External
wait
PSEN#/RD#/WR# and/or by extending ALE. In the
table, Notes 3 and 5 mark parameters affected by an
5.2 Definition of AC Symbols
5.3 A.C. Characteristics
Test Conditions: Capacitive load on all pins = 50 pF.
F
T
T
T
T
NOTES:
1.
2.
3.
4.
5.
Symbol
OSC
AVLL
OSC
LHLL
LLAX
PRELIMINARY
16 MHz.
Specifications for PSEN# are identical to those for RD#.
In the formula, M=Number of wait states (0 or 1) for ALE.
In the formula, N=Number of wait states (0,1,2, or 3) for RD#/PSEN#/WR#.
“Typical” specifications are untested and not guaranteed.
states
1/F
ALE Pulse Width
Address Valid to ALE Low
Address Hold after ALE Low
XTAL1 Frequency
OSC
can
@ 12 MHz
@ 16 MHz
@ 12 MHz
@ 16 MHz
@ 12 MHz
@ 16 MHz
@ 12 MHz
@ 16 MHz
8XC251SA/SB/SP/SQ HIGH-PERFORMANCE CHMOS MICROCONTROLLER
be
A
D
L
Q
R
W
added
Parameter
Table 10. AC Timing Symbol Definitions
Signals
Address
Data In
ALE
Data Out
RD#/PSEN#
WR#
by
Table 11. AC Characteristics
extending
H
L
V
X
Z
ALE wait state, and Notes 4 and 5 mark parameters
affected by a PSEN#/RD#/WR# wait state.
Figures 8–10 show the bus cycles with the timing
parameters.
N/A
N/A
73.3
52.5
58.3
37.5
15
15
@ Max F
Min
Conditions
High
Low
Valid
No Longer Valid
Floating
N/A
N/A
osc
Max
(1)
T
T
(1+2M)
(1+2M)
OSC
OSC
83.3
62.5
Min
15
0
F
– 10
– 25
osc
Variable
Max
16
Units
MHz
(3)
(3)
ns
ns
ns
ns
19