Rainbow Electronics Atmega169L - Manual (Page 191)

191
ATmega169V/L
2514A–AVR–08/02
Analog to Digital
Converter
Features • 10-bit Resolution
• 0.5 LSB Integral Non-linearity
• ± 2 LSB Absolute Accuracy
• TBD - 260 µs Conversion Time
• Up to TBD kSPS at Maximum Resolution
• Eight Multiplexed Single Ended Input Channels
• Seven Differential input channels
• Optional Left Adjustment for ADC Result Readout
• 0 - V
CC
ADC Input Voltage Range
• Selectable 1.1V ADC Reference Voltage
• Free Running or Single Conversion Mode
• ADC Start Conversion by Auto Triggering on Interrupt Sources
• Interrupt on ADC Conversion Complete
• Sleep Mode Noise Canceler
The ATmega169 features a 10-bit successive approximation ADC. The ADC is con-
nected to an 8-channel Analog Multiplexer which allows eight single-ended voltage
inputs constructed from the pins of Port A. The single-ended voltage inputs refer to 0V
(GND).
The device also supports 16 differential voltage input combinations. Seven differential
analog input channels share a common negative terminal (ADC1), while any other ADC
input can be selected as the positive input terminal.
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 82.
The ADC has a separate analog supply voltage pin, AVCC. AVCC must not differ more
than ± 0.3V from V
CC
. See the paragraph “ADC Noise Canceler” on page 198 on how to
connect this pin.
Internal reference voltages of nominally 1.1V or AVCC are provided On-chip. The volt-
age reference may be externally decoupled at the AREF pin by a capacitor for better
noise performance.