ATmega88 Atmel Corporation, ATmega88 Datasheet - Page 244

• Manufacturer Part Number: ATmega88
• Manufacturer: Atmel Corporation

Specifications of ATmega88

• Flash (kbytes): 8 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 24
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 1
• Eeprom (bytes): 512
• 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: 3
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

24. Analog-to-digital converter
24.1
24.2
2545T–AVR–05/11
Features
Overview
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The Atmel ATmega48/88/168 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 PortC. 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
The ADC has a separate analog supply voltage pin, AV
from V
Internal reference voltages of nominally 1.1V or AV
ence may be externally decoupled at the AREF pin by a capacitor for better noise performance.
The Power Reduction ADC bit, PRADC, in
disabled by writing a logical zero to enable the ADC.
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, AV
nected to the AREF pin by writing to the REFSn bits in the ADMUX Register. The internal
voltage reference may thus be decoupled by an external capacitor at the AREF pin to improve
noise immunity.
10-bit resolution
0.5LSB integral non-linearity
±2LSB absolute accuracy
13µs - 260µs conversion time
Up to 76.9kSPS (Up to 15kSPS at maximum resolution)
Six multiplexed single ended input channels
Two additional multiplexed single ended input channels (TQFP and QFN/MLF package only)
Optional left adjustment for ADC result readout
0 - V
Selectable 1.1V ADC reference voltage
Free running or single conversion mode
Interrupt on ADC conversion complete
Sleep mode noise canceler
CC
CC
245.
ADC input voltage range
. See the paragraph
“ADC noise canceler” on page 250
“Minimizing power consumption” on page 41
CC
or an internal 1.1V reference voltage may be con-
CC
CC
are provided On-chip. The voltage refer-
. AV
CC
ATmega48/88/168
must not differ more than ±0.3V
on how to connect this pin.
Figure 24-1
must be
244