Rainbow-electronics Atmega169L Manual do Utilizador descarregar pdf (Página 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

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

. 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.

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Rainbow-electronics Atmega169L Manual do Utilizador Página 191