Datasheet

132
8006H–AVR–10/09
ATtiny24/44/84
16. Analog to Digital Converter
16.1 Features
• 10-bit Resolution
• 1.0 LSB Integral Non-linearity
• ± 2 LSB Absolute Accuracy
• 13µs Conversion Time
• 15 kSPS at Maximum Resolution
• Eight Multiplexed Single Ended Input Channels
• Twelve Differential Input Channels with Selectable Gain (1x, 20x)
• Temperature Sensor Input Channel
• Optional Left Adjustment for ADC Result Readout
• 0 - V
CC
ADC Input Voltage Range
• 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
• Unipolar / Bipolar Input Mode
• Input Polarity Reversal Mode
16.2 Overview
The ATtiny24/44/84 features a 10-bit successive approximation ADC. The ADC is connected to
8-pin port A for external sources. In addition to external sources internal temperature sensor can
be measured by ADC. Analog Multiplexer allows eight single-ended channels or 12 differential
channels from Port A. The programmable gain stage provides ampification steps 0 dB (1x) and
26 dB (20x) for 12 differential ADC channels.
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 16-1
on page 133.
Internal reference voltage of nominally 1.1V is provided On-chip. Alternatively, V
CC
can be used
as reference voltage for single ended channels. There is also an option to use an external volt-
age reference and turn-off the internal voltage reference.