W79E225A_08 Datasheet, PDF (188/203 Pages) Winbond – 8-bit Microcontroller

Preliminary W79E225A/226A/227A Data Sheet
24.3 AC Characteristics
tCLCL
tCLCH
tCLCX
$MPDL
tCHCL
tCHCX


Note: Duty cycle is 50%.
24.3.1 External Clock Characteristics
PARAMETER
Clock High Time
Clock Low Time
Clock Rise Time
Clock Fall Time
SYMBOL
t_CHCX
t_CLCX
t_CLCH
t_CHCL
MIN.
12
12
-
-
TYP.
-
-
-
-
MAX.
-
-
10
10
UNITS
nS
nS
nS
nS
NOTES
24.3.2 AC Specification
(VDD − VSS = 5V ±10%, TA = 25°C, Fosc = 20 MHz, unless otherwise specified.)
PARAMETER
Oscillator Frequency
Oscillator Frequency
ALE Pulse Width
Address Valid to ALE Low
Address Hold After ALE Low
Address Hold After ALE Low for
MOVX Write
SYMBOL
1/t_CLCL
1/t_CLCL
t_LHLL
t_AVLL
t_LLAX1
t_LLAX2
VARIABLE
CLOCK
MIN.
0
0
1.5t_CLCL - 5
0.5t_CLCL - 5
0.5t_CLCL - 5
0.5t_CLCL - 5
VARIABLE
CLOCK
MAX.
40¹
24²
ALE Low to Valid Instruction In
t_LLIV
ALE Low to PSEN Low
t_LLPL
0.5t_CLCL - 5
2.5t_CLCL - 20
PSEN Pulse Width
t_PLPH
2.0t_CLCL - 5
PSEN Low to Valid Instruction In
t_PLIV
2.0t_CLCL - 20
Input Instruction Hold After PSEN
t_PXIX
0
Input Instruction Float After PSEN
t_PXIZ
Port 0 Address to Valid Instr. In
t_AVIV1
t_CLCL - 5
3.0t_CLCL - 20
UNITS
MHz
MHz
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
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Publication Release Date: April 15, 2008
Revision A4.0