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7682C–AUTO–04/08
AT90CAN32/64/128
27.9
External Data Memory Characteristics(1)
Notes:
1. All DC Characteristics contained in this datasheet are based on simulation and characterization of other AVR microcontrol-
lers manufactured in the same process technology. These values are preliminary values representing design targets, and
will be updated after characterization of actual silicon.
2. This assumes 50% clock duty cycle. The half period is actually the high time of the external clock, XTAL1.
3. This assumes 50% clock duty cycle. The half period is actually the low time of the external clock, XTAL1.
Table 27-7.
External Data Memory Characteristics, VCC = 4.5 - 5.5 Volts, No Wait-state
Symbol
Parameter
8 MHz Oscillator
Variable Oscillator
Unit
Min.
Max.
Min.
Max.
0
1/tCLCL
Oscillator Frequency
0.0
16
MHz
1
tLHLL
ALE Pulse Width
115
1.0 tCLCL – 10
ns
2
tAVLL
Address Valid A to ALE Low
57.5
0.5 tCLCL – 5
ns
3a
tLLAX_ST
Address Hold After ALE Low,
write access
5
ns
3b
tLLAX_LD
Address Hold after ALE Low,
read access
5
ns
4
tAVLLC
Address Valid C to ALE Low
57.5
0.5 tCLCL – 5
ns
5
tAVRL
Address Valid to RD Low
115
1.0 tCLCL – 10
ns
6
tAVWL
Address Valid to WR Low
115
1.0 tCLCL – 10
ns
7
tLLWL
ALE Low to WR Low
47.5
67.5
0.5 tCLCL – 15
0.5 tCLCL + 5
ns
8
tLLRL
ALE Low to RD Low
47.5
67.5
0.5 tCLCL – 15
0.5 tCLCL + 5
ns
9
tDVRH
Data Setup to RD High
40
ns
10
tRLDV
Read Low to Data Valid
75
1.0 tCLCL – 50
ns
11
tRHDX
Data Hold After RD High
0
ns
12
tRLRH
RD Pulse Width
115
1.0 tCLCL – 10
ns
13
tDVWL
Data Setup to WR Low
42.5
0.5 tCLCL – 20
ns
14
tWHDX
Data Hold After WR High
115
1.0 tCLCL – 10
ns
15
tDVWH
Data Valid to WR High
125
1.0 tCLCL
ns
16
tWLWH
WR Pulse Width
115
1.0 tCLCL – 10
ns
Table 27-8.
External Data Memory Characteristics, VCC = 4.5 - 5.5 Volts, 1 Cycle Wait-state
Symbol
Parameter
8 MHz Oscillator
Variable Oscillator
Unit
Min.
Max.
Min.
Max.
0
1/tCLCL
Oscillator Frequency
0.0
16
MHz
10
tRLDV
Read Low to Data Valid
200
2.0 tCLCL – 50
ns
12
tRLRH
RD Pulse Width
240
2.0 tCLCL – 10
ns
15
tDVWH
Data Valid to WR High
240
2.0 tCLCL
ns
16
tWLWH
WR Pulse Width
240
2.0 tCLCL – 10
ns