atmega323l ATMEL Corporation, atmega323l Datasheet - Page 131

• Manufacturer Part Number: atmega323l
• Description: Atmega323 8-bit Avr Microcontroller With 32k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

ADC Noise Canceler
Function
1457G–AVR–09/03
Figure 64. ADC Timing Diagram, Free Run Conversion
Table 44. ADC Conversion Time
The ADC features a noise canceler that enables conversion during ADC Noise Reduc-
tion mode (see “Sleep Modes” on page 39) to reduce noise induced from the CPU core
and other I/O peripherals. If other I/O peripherals must be active during conversion, this
mode works equivalently for Idle mode. To make use of this feature, the following proce-
dure should be used:
1. Make sure that the ADC is enabled and is not busy converting. Single Conver-
2. Enter ADC Noise Reduction mode (or Idle mode). The ADC will start a conver-
3. If no other interrupts occur before the ADC conversion completes, the ADC inter-
Condition
Extended Conversion
Normal Conversions
sion mode must be selected and the ADC conversion complete interrupt must be
enabled.
ADEN = 1
ADSC = 0
ADFR = 0
ADIE = 1
sion once the CPU has been halted.
rupt will wake up the CPU and execute the ADC Conversion Complete interrupt
routine.
Cycle Number
ADC Clock
ADSC
ADIF
ADCH
ADCL
Sample & Hold (Cycles from
Conversion
Complete
Start of Conversion)
One Conversion
11
12
13.5
1.5
13
Next Conversion
1
Sign and MSB of Result
LSB of Result
2
MUX and REFS
Update
Time (Cycles)
3
Conversion
ATmega323(L)
Sample & Hold
25
13
4
Conversion
Time (µs)
125 - 500
65 - 260
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