ATtiny261 Atmel Corporation, ATtiny261 Datasheet - Page 142

• Manufacturer Part Number: ATtiny261
• Manufacturer: Atmel Corporation

Specifications of ATtiny261

• Flash (kbytes): 2 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 4
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 16
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

15. ADC – Analog to Digital Converter
15.1
15.2
142
Features
Overview
ATtiny261/461/861
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The ATtiny261/461/861 features a 10-bit successive approximation ADC. The ADC is connected
to a 11-channel Analog Multiplexer which allows 16 differential voltage input combinations and
11 single-ended voltage inputs constructed from the pins PA7:PA0 or PB7:PB4. The differential
input is equipped with a programmable gain stage, providing amplification steps of 1x, 8x, 20x or
32x on the differential input voltage before the A/D conversion. 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
on page
Internal reference voltages of nominally 1.1V or 2.56V are provided On-chip. The Internal refer-
ance voltage of 2.56V, can optionally be externally decoupled at the AREF (PA3) pin by a
capacitor, for better noise performance. Alternatively, V
single ended channels. There is also an option to use an external voltage reference and turn-off
the internal voltage reference. These options are selected using the REFS2:0 bits of the ADC-
SRB and ADMUX registers.
10-bit Resolution
1.0 LSB Integral Non-linearity
± 2 LSB Absolute Accuracy
13µs Conversion Time
15 kSPS at Maximum Resolution
11 Multiplexed Single Ended Input Channels
16 Differential input pairs
15 Differential input pairs with selectable gain
Temperature Sensor Input Channel
Optional Left Adjustment for ADC Result Readout
0 - V
Selectable 1.1V / 2.56V ADC Voltage Reference
Free Running or Single Conversion Mode
ADC Start Conversion by Auto Triggering on Interrupt Sources
Interrupt on ADC Conversion Complete
Sleep Mode Noise Cancele
Unipolar / Bipolar Input Mode
Input Polarity Reversal Mode
CC
143.
ADC Input Voltage Range
CC
can be used as reference voltage for
2588E–AVR–08/10
Figure 15-1