Rainbow Electronics ATmega161L - Manual (Page 134)

134
ATmega161(L)
1228C–AVR–08/02
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