
205
2570N–AVR–05/11
ATmega325/3250/645/6450
with Auto triggering from a source other than the ADC Conversion Complete, each conversion
will require 25 ADC clocks. This is because the ADC must be disabled and re-enabled after
every conversion.
In Free Running mode, a new conversion will be started immediately after the conversion com-
pletes, while ADSC remains high. For a summary of conversion times, see
Table 23-1.Figure 23-4. ADC Timing Diagram, First Conversion (Single Conversion Mode)
Figure 23-5. ADC Timing Diagram, Single Conversion
Figure 23-6. ADC Timing Diagram, Auto Triggered Conversion
Sign and MSB of Result
LSB of Result
ADC Clock
ADSC
Sample & Hold
ADIF
ADCH
ADCL
Cycle Number
ADEN
1
212
13
14
15
16
17
18
19
20
21
22
23
24
25
1
2
First Conversion
Next
Conversion
3
MUX and REFS
Update
MUX and REFS
Update
Conversion
Complete
1
2
3
4
5
6
7
8
9
10
11
12
13
Sign and MSB of Result
LSB of Result
ADC Clock
ADSC
ADIF
ADCH
ADCL
Cycle Number
12
One Conversion
Next Conversion
3
Sample & Hold
MUX and REFS
Update
Conversion
Complete
MUX and REFS
Update
1
2
3
4
5
6
7
8
9
10
11
12
13
Sign and MSB of Result
LSB of Result
ADC Clock
Trigger
Source
ADIF
ADCH
ADCL
Cycle Number
12
One Conversion
Next Conversion
Conversion
Complete
Prescaler
Reset
ADATE
Prescaler
Reset
Sample &
Hold
MUX and REFS
Update