AC Characteristics
Under operating conditions, load capacitance for Port 0, ALE/PROG, and PSEN = 100 pF; load capacitance for all other
outputs = 80 pF.
External Program and Data Memory Characteristics
Variable Oscillator
Symbol
1/tCLCL
tLHLL
Parameter
Min
0
Max
Units
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Oscillator Frequency
24
ALE Pulse Width
2tCLCL - 40
tCLCL - 13
tCLCL - 20
tAVLL
Address Valid to ALE Low
Address Hold after ALE Low
ALE Low to Valid Instruction In
ALE Low to PSEN Low
PSEN Pulse Width
tLLAX
tLLIV
4tCLCL - 65
tLLPL
tCLCL - 13
tPLPH
tPLIV
3tCLCL - 20
PSEN Low to Valid Instruction In
Input Instruction Hold after PSEN
Input Instruction Float after PSEN
PSEN to Address Valid
Address to Valid Instruction In
PSEN Low to Address Float
RD Pulse Width
3tCLCL - 45
tCLCL - 10
tPXIX
0
tPXIZ
tPXAV
tAVIV
tCLCL - 8
5tCLCL - 55
10
tPLAZ
tRLRH
tWLWH
tRLDV
tRHDX
tRHDZ
tLLDV
tAVDV
tLLWL
tAVWL
tQVWX
tQVWH
tWHQX
tRLAZ
tWHLH
6tCLCL - 100
6tCLCL - 100
WR Pulse Width
RD Low to Valid Data In
Data Hold after RD
5tCLCL - 90
0
Data Float after RD
2tCLCL - 28
8tCLCL - 150
9tCLCL - 165
3tCLCL + 50
ALE Low to Valid Data In
Address to Valid Data In
ALE Low to RD or WR Low
Address to RD or WR Low
Data Valid to WR Transition
Data Valid to WR High
Data Hold after WR
3tCLCL - 50
4tCLCL - 75
tCLCL - 20
7tCLCL - 120
tCLCL - 20
RD Low to Address Float
RD or WR High to ALE High
0
tCLCL - 20
tCLCL + 25
32
AT89S8252
0401G–MICRO–3/06
ATMEL [ ATMEL ]
