329
2467S–AVR–07/09
ATmega128
Table 139.
External Data Memory Characteristics, 4.5 - 5.5 Volts, SRWn1 = 1, SRWn0 = 0
Symbol
Parameter
4 MHz Oscillator
Variable Oscillator
Unit
Min
Max
Min
Max
0
1/t
CLCL
Oscillator Frequency
0.0
16
MHz
10
t
RLDV
Read Low to Data Valid
325
3.0t
CLCL
-50
ns
12
t
RLRH
RD Pulse Width
365
3.0t
CLCL
-10
ns
15
t
DVWH
Data Valid to WR High
375
3.0t
CLCL
ns
16
t
WLWH
WR Pulse Width
365
3.0t
CLCL
-10
ns
Table 140.
External Data Memory Characteristics, 4.5 - 5.5 Volts, SRWn1 = 1, SRWn0 = 1
Symbol
Parameter
4 MHz Oscillator
Variable Oscillator
Unit
Min
Max
Min
Max
0
1/t
CLCL
Oscillator Frequency
0.0
16
MHz
10
t
RLDV
Read Low to Data Valid
325
3.0t
CLCL
-50
ns
12
t
RLRH
RD Pulse Width
365
3.0t
CLCL
-10
ns
14
t
WHDX
Data Hold After WR High
240
2.0t
CLCL
-10
ns
15
t
DVWH
Data Valid to WR High
375
3.0t
CLCL
ns
16
t
WLWH
WR Pulse Width
365
3.0t
CLCL
-10
ns
Table 141.
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
8
MHz
1
t
LHLL
ALE Pulse Width
235
t
CLCL
-15
ns
2
t
AVLL
Address Valid A to ALE Low
115
0.5t
CLCL
ns
3a
t
LLAX_ST
Address Hold After ALE Low,
write access
5
5
ns
3b
t
LLAX_LD
Address Hold after ALE Low,
read access
5
5
ns
4
t
AVLLC
Address Valid C to ALE Low
115
0.5t
CLCL
ns
5
t
AVRL
Address Valid to RD Low
235
1.0t
CLCL
-15
ns
6
t
AVWL
Address Valid to WR Low
235
1.0t
CLCL
-15
ns
7
t
LLWL
ALE Low to WR Low
115
130
0.5t
CLCL
0.5t
CLCL
+5
ns
8
t
LLRL
ALE Low to RD Low
115
130
0.5t
CLCL
0.5t
CLCL
+5
ns
9
t
DVRH
Data Setup to RD High
45
45
ns
10
t
RLDV
Read Low to Data Valid
190
1.0t
CLCL
-60
ns
11
t
RHDX
Data Hold After RD High
0
0
ns