DS87C550 Datasheet, PDF (37/50 Pages) Dallas Semiconductor – EPROM High-Speed Micro with A/D and PWM

TYPICAL I_CC VERSUS FREQUENCY
DS87C550
AC ELECTRICAL CHARACTERISTICS
PARAMETER
SYMBOL
33 MHz
MIN MAX
Oscillator Freq. (Ext. Osc.)
(Ext. Crystal)
1/t_CLCL
0
1
33
33
ALE Pulse Width
t_LHLL
40
Port 0 Address Valid to ALE
Low
t_AVLL
10
Address Hold after ALE Low t_LLAX1
10
ALE Low to Valid
Instruction In
t_LLIV
56
ALE Low to PSEN Low
t_LLPL
10
PSEN Pulse Width
t_PLPH
55
PSEN Low to Valid
Instruction In
t_PLIV
41
Input Instruction Hold after
PSEN
t_PXIX
0
Input Instruction Float after
PSEN
t_PXIZ
26
Port 0 Address to Valid
Instruction In
t_AVIV
71
Port 2 Address to Valid
Instruction In
t_AVIV2
81
PSEN Low to Address Float
t_PLAZ
0
VARIABLE CLOCK
MIN
MAX
0
33
1
33
0.375 t_MCS -5
0.125 t_MCS -5
0.125 t_MCS -5
0.125 t_MCS -5
0.5 t_MCS -5
0.625
t_MCS -20
0.5t_MCS
-20
0
0.25t_MCS
-5
0.75t_MCS
-20
0.875
t_MCS -25
0
UNITS
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
NOTES FOR AC ELECTRICAL CHARACTERISTICS
§ The value for t_MCS is a time period related to the machine cycle clock in terms of the processor’s input
clock frequency. Its value is highlighted in the table “STRETCH VALUE TIMING” for all possible
settings of the 4X/ 2X and CD1:0 bits. The default condition is CD1 = 1 and CD0 = 0, where 4X/ 2X
is disregarded.
§ All parameters apply to both commercial and industrial temperature operation unless otherwise noted.
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