ATMEGA8_14 Datasheet, PDF (189/331 Pages) ATMEL Corporation – High-performance, Low-power Atmel

Analog-to-
Digital
Converter
Features
ATmega8(L)
• 10-bit Resolution
• 0.5 LSB Integral Non-linearity
• ±2 LSB Absolute Accuracy
• 13µs - 260µs Conversion Time
• Up to 15 kSPS at Maximum Resolution
• 6 Multiplexed Single Ended Input Channels
• 2 Additional Multiplexed Single Ended Input Channels (TQFP and QFN/MLF Package only)
• Optional Left Adjustment for ADC Result Readout
• 0 - V_CC ADC Input Voltage Range
• Selectable 2.56V ADC Reference Voltage
• Free Running or Single Conversion Mode
• Interrupt on ADC Conversion Complete
• Sleep Mode Noise Canceler
The ATmega8 features a 10-bit successive approximation ADC. The ADC is connected to an 8-
channel Analog Multiplexer which allows eight single-ended voltage inputs constructed from the
pins of Port C. The single-ended voltage inputs refer to 0V (GND).
The ADC contains a Sample and Hold circuit which ensures that the input voltage to the ADC is
held at a constant level during conversion. A block diagram of the ADC is shown in Figure 90 on
page 190.
The ADC has a separate analog supply voltage pin, AV_CC. AV_CC must not differ more than ±0.3V
from V_CC. See the paragraph “ADC Noise Canceler” on page 195 on how to connect this pin.
Internal reference voltages of nominally 2.56V or AV_CC are provided On-chip. The voltage refer-
ence may be externally decoupled at the AREF pin by a capacitor for better noise performance.
2486AA–AVR–02/2013
189