Analog-to-
Digital
Converter
Features
• 10-bit Resolution
• 0.5 LSB Integral Non-linearity
•
2 LSB Absolute Accuracy
• 13 - 260 µs 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 - VCC 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.
The ADC has a separate analog supply voltage pin, AVCC. AVCC must not differ more than
0.3V from VCC. See the paragraph “ADC Noise Canceler” on page 201 on how to connect this
pin.
Internal reference voltages of nominally 2.56V or AVCC are provided On-chip. The voltage refer-
ence may be externally decoupled at the AREF pin by a capacitor for better noise performance.
196
ATmega8(L)
2486T–AVR–05/08
ATMEL [ ATMEL ]
