132
ATmega161(L)
1228B–09/01
Table 53.
External Data Memory Characteristics, 4.0 - 5.5 Volts, SRWn1 = 1, SRWn0 = 0
Symbol
Parameter
8 MHz Oscillator
Variable Oscillator
Unit
Min
Max
Min
Max
0
1/t
CLCL
Oscillator Frequency
0.0
8.0
MHz
10
t
RLDV
Read Low to Data Valid
310
3.0t
CLCL
-65
ns
12
t
RLRH
RD Pulse Width
355
3.0t
CLCL
-20
ns
15
t
DVWH
Data Valid to WR High
345
3.0t
CLCL
-30
ns
16
t
WLWH
WR Pulse Width
35
3.0t
CLCL
-20
ns
Table 54.
External Data Memory Characteristics, 4.0 - 5.5 Volts, SRWn1 = 1, SRWn0 = 1
Symbol
Parameter
8 MHz Oscillator
Variable Oscillator
Unit
Min
Max
Min
Max
0
1/t
CLCL
Oscillator Frequency
0.0
8.0
MHz
10
t
RLDV
Read Low to Data Valid
310
3.0t
CLCL
-65
ns
12
t
RLRH
RD Pulse Width
355
3.0t
CLCL
-20
ns
14
t
WHDX
Data Hold After WR High
152.5
1.5t
CLCL
-35
ns
15
t
DVWH
Data Valid to WR High
345
3.0t
CLCL
-30
ns
16
t
WLWH
WR Pulse Width
355
3.0t
CLCL
-20
ns
Table 55.
External Data Memory Characteristics, 2.7 - 5.5 Volts, No Wait State
Symbol
Parameter
4 MHz Oscillator
Variable Oscillator
Unit
Min
Max
Min
Max
0
1/t
CLCL
Oscillator Frequency
0.0
4.0
MHz
1
t
LHLL
ALE Pulse Width
195
t
CLCL
-55
ns
2
t
AVLL
Address Valid A to ALE Low
60
0.5t
CLCL
-65
ns
3a
t
LLAX_ST
Address Hold After ALE Low,
write access
10
10
ns
3b
t
LLAX_LD
Address Hold after ALE Low,
read access
15
15
ns
4
t
AVLLC
Address Valid C to ALE Low
60
0.5t
CLCL
-65
ns
5
t
AVRL
Address Valid to RD Low
200
1.0t
CLCL
-50
ns
6
t
AVWL
Address Valid to WR Low
200
1.0t
CLCL
-50
ns
7
t
LLWL
ALE Low to WR Low
105
145
0.5t
CLCL
-20
0.5t
CLCL
+20
ns
8
t
LLRL
ALE Low to RD Low
105
145
0.5t
CLCL
-20
0.5t
CLCL
+20
ns
9
t
DVRH
Data Setup to RD High
95
95
ns
10
t
RLDV
Read Low to Data Valid
165
165
ns
11
t
RHDX
Data Hold After RD High
0
0
ns