Datasheet

Table Of Contents
367
ATmega640/V-1280/V-1281/V-2560/V-2561/V [DATASHEET]
2549Q–AVR–02/2014
Note: Values are guidelines only.
31.9 External Data Memory Timing
Notes: 1. This assumes 50% clock duty cycle. The half period is actually the high time of the external clock, XTAL1.
Conversion Time 65 260 µs
AVCC Analog Supply Voltage V
CC
- 0.3 V
CC
+ 0.3
V
V
REF
Reference Voltage 2.7 AVCC - 0.5
V
IN
Input Voltage GND V
CC
V
DIFF
Input Differential Voltage -V
REF
/Gain V
REF
/Gain
ADC Conversion Output -511 511 LSB
Input Bandwidth 4kHz
V
INT
Internal Voltage Reference 2.3 2.56 2.8 V
R
REF
Reference Input Resistance 32 k
R
AIN
Analog Input Resistance 100 M
Table 31-11. External Data Memory Characteristics, 4.5 to 5.5 Volts, No Wait-state
Symbol Parameter
8MHz Oscillator Variable Oscillator
UnitMin. Max. Min. Max.
01/t
CLCL
Oscillator Frequency 0.0 16 MHz
1t
LHLL
ALE Pulse Width 115 1.0t
CLCL
-10
ns
2t
AVLL
Address Valid A to ALE Low 57.5 0.5t
CLCL
-5
(1)
3a t
LLAX_ST
Address Hold After ALE Low,
write access
55
3b t
LLAX_LD
Address Hold after ALE Low,
read access
55
4t
AVLLC
Address Valid C to ALE Low 57.5 0.5t
CLCL
-5
(1)
5t
AVRL
Address Valid to RD Low 115 1.0t
CLCL
-10
6t
AVWL
Address Valid to WR Low 115 1.0t
CLCL
-10
7t
LLWL
ALE Low to WR Low 47.5 67.5 0.5t
CLCL
-15
(2)
0.5t
CLCL
+5
(2)
8t
LLRL
ALE Low to RD Low 47.5 67.5 0.5t
CLCL
-15
(2)
0.5t
CLCL
+5
(2)
9t
DVRH
Data Setup to RD High 40 40
10 t
RLDV
Read Low to Data Valid 75 1.0t
CLCL
-50
11 t
RHDX
Data Hold After RD High 0 0
12 t
RLRH
RD Pulse Width 115 1.0t
CLCL
-10
13 t
DVWL
Data Setup to WR Low 42.5 0.5t
CLCL
-20
(1)
14 t
WHDX
Data Hold After WR High 115 1.0t
CLCL
-10
15 t
DVWH
Data Valid to WR High 125 1.0t
CLCL
16 t
WLWH
WR Pulse Width 115 1.0t
CLCL
-10
Table 31-10. ADC Characteristics, Differential Channels (Continued)
Symbol Parameter Condition Min.
(1)
Typ.
(1)
Max.
(1)
Unit
s