Sonic Alert msm85c154hvs User Manual
ELECTRICAL CHARACTERISTICS
221
6.4 External Program Memory Access AC Characteristics
V
CC
=2.2 to 6.0V, V
SS
=0V, Ta=–40
°
C to +85
°
C
PORT 0, ALE, and
PSEN
connected with 100pF load, other connected with 80pF load
Parameter
Symble
Unit
Min.
Max.
1 to 24 MHz
Variable clock from
41.7
1000
ns
t
CLCL
XTAL1, XTAL 2 Oscillation Cycle
2t
CLCL
-40
—
ns
t
LHLL
ALE Signal Width
1t
CLCL
-15
—
ns
t
AVLL
Address Setup Time
(to ALE Falling Edge)
1t
CLCL
-35
—
ns
t
LLAX
Address Hold Time
(from ALE Falling Edge)
—
4t
CLCL
-100
ns
t
LLPL
Instruction Data Read Time
(from ALE Falling Edge)
1t
CLCL
-30
—
ns
t
LLPL
From ALE Falling Edge to
PSEN
Falling Edge
3t
CLCL
-35
—
ns
t
PLPH
PSEN Signal Width
—
3t
CLCL
-45
ns
t
PLIV
Instruction Data Read Time
(from
PSEN Falling Edge)
0
—
ns
t
PXIX
Instruction Data Hold Time
(from
PSEN Rising Edge)
—
1t
CLCL
-20
ns
t
PXIZ
Bus Floating Time after Instruction
Data Read (from
PSEN Rising Edge)
—
5t
CLCL
-105
ns
t
AVIV
Instruction Data Read Time
(from Address Output)
0
—
ns
t
AZPL
Bus Floating Time(
PSEN Rising
Edge from Address float)
1t
CLCL
-20
—
ns
t
PXAV
Address Output Time from
PSEN
Rising Edge
*1
*1 The variable check is from 0 to 24 MHz when the external check is used.