ATtiny26 Atmel Corporation, ATtiny26 Datasheet - Page 95

• Manufacturer Part Number: ATtiny26
• Manufacturer: Atmel Corporation

Specifications of ATtiny26

• Flash (kbytes): 2 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 11
• 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: No
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: NO
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 3
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

Operation
1477K–AVR–08/10
Figure 51. Analog to Digital Converter Block Schematic
The ADC converts an analog input voltage to a 10-bit digital value through successive approxi-
mation. The minimum value represents GND and the maximum value represents the voltage on
the AREF pin minus 1 LSB. Optionally, AVCC or and internal 2.56V reference voltage may be
connected to the AREF pin by writing to the REFS bits in ADMUX. The internal voltage refer-
ence may thus be decoupled by an external capacitor at the AREF pin to improve noise
immunity.
The analog input channel and differential gain are selected by writing to the MUX bits in
ADMUX. Any of the 11 ADC input pins ADC10..0, as well as GND and a fixed bandgap voltage
reference of nominally 1.18V (V
tion of ADC input pins can be selected as positive and negative inputs to the differential gain
amplifier.
If differential channels are selected, the differential gain stage amplifies the voltage difference
between the selected input channel pair by the selected gain factor. Note that the voltage on the
positive input terminal must be higher than on the negative input terminal, otherwise the gain
ADC10
ADC9
ADC8
ADC7
ADC6
ADC5
ADC4
ADC3
ADC2
ADC1
ADC0
AREF
GND
VCC
8-BIT DATA BUS
REFERENCE
INTERNAL 1.18 V
INTERNAL
2.56 V
REFERENCE
INPUT
INPUT
POS.
MUX
NEG.
MUX
ADC MULTIPLEXER
BG
SELECT (ADMUX)
), can be selected as single ended inputs to the ADC. A selec-
MUX DECODER
+
-
GAIN
AMPLIFIER
DIFFERENTIAL SELECTION
SINGLE ENDED /
10-BIT DAC
ADC CTRL. & STATUS
REGISTER (ADCSR)
ADC CONVERSION
COMPLETE IRQ
PRESCALER
CONVERSION LOGIC
SAMPLE & HOLD
COMPARATOR
+
-
15
ADC DATA REGISTER
(ADCH/ADCL)
MULTIPLEXER OUTPUT
ADC
0
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