GMS90 Series
HYUNDAI MicroElectronics
AC Characteristics
Explanation of the AC Symbols
Each timing symbol has 5 characters. The first character is always a ‘t’ (stand for time). The other characters,
depending on their positions, stand for the name of a signal or the logical status of that signal. The following is
a list of all the characters and what they stand for.
A: Address
T: Time
C: Clock
V: Valid
D: Input Data
W: WR signal
X: No longer a valid logic level
Z: Float
H: Logic level HIGH
I: Instruction (program memory contents)
L: Logic level LOW, or ALE
P: PSEN
For example,
Q: Output Data
t
AVLL = Time from Address Valid to ALE Low
R: RD signal
tLLPL = Time from ALE Low to PSEN Low
AC Characteristics for GMS90 series (12MHz version)
VCC= 5V :
VCC= 5V + 10%, − 15%; VSS= 0V; TA= 0°C to 70°C
(CL for port 0. ALE and PSEN outputs = 100pF; CL for all other outputs = 80pF)
V
CC= 3.3V :
VCC= 3.3V + 0.3V, − 0.6V; VSS= 0V; TA= 0°C to 70°C
(CL for port 0. ALE and PSEN outputs = 50pF; CL for all other outputs = 50pF)
Variable clock :
Vcc = 5V : 1/tCLCL = 3.5 MHz to 12 MHz
Vcc = 3.3V : 1/tCLCL = 1 MHz to 12 MHz
External Program Memory Characteristics
Variable Oscillator
1/tCLCL = 3.5 to 12MHz
12 MHz Oscillator
Parameter
Symbol
Unit
Min.
127
43
30
-
Max.
Min.
Max.
tLHLL
-
2tCLCL-40
-
ALE pulse width
ns
ns
ns
ns
ns
ns
ns
ns
tAVLL
tLLAX
tLLIV
-
tCLCL-40
-
Address setup to ALE
-
233
-
tCLCL-53
-
Address hold after ALE
ALE low to valid instruction in
ALE to PSEN
-
4tCLCL-100
tLLPL
tPLPH
tPLIV
tPXIX
58
215
-
tCLCL-25
-
-
3tCLCL-35
-
PSEN pulse width
150
-
-
0
-
3tCLCL-100
-
PSEN to valid instruction in
Input instruction hold after PSEN
Input instruction float after PSEN
0
†
-
63
tCLCL-20
ns
ns
tPXIZ
†
75
-
tCLCL-8
-
Address valid after PSEN
tPXAV
Oct. 2000 Ver 3.1a
31
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