ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 292

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 14
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 26
• Ext Interrupts: 13
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 3.3
• Eeprom (bytes): 1024
• Self Program Memory: YES
• 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: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

24. Analog to Digital Converter - ADC
24.1
7766F–AVR–11/10
Features
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The ATmega16U4/ATmega32U4 features a 10-bit successive approximation ADC. The ADC is
connected to an 12-channel Analog Multiplexer which allows six single-ended voltage inputs
constructed from several pins of Port B, D and F. The single-ended voltage inputs refer to
0V (GND).
The device also supports 32 differential voltage input combinations, thanks to a differential
amplifier equipped with a programmable gain stage, providing amplification steps of 0 dB (1x),
10 dB (10x), 16dB (40x) or 23dB (200x) on the differential input voltage before the A/D conver-
sion. Two differential analog input channels share a common negative terminal (ADC0/ADC1),
while any other ADC input can be selected as the positive input terminal. If 1x, 10x or 40x gain is
used, 8-bit resolution can be expected. If 200x gain is used, 7-bit resolution can be expected.
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
The ADC has a separate analog supply voltage pin, AV
0.3V from V
pin.
Internal reference voltages of nominally 2.56V or AV
ence may be externally decoupled at the AREF pin by a capacitor for better noise performance.
10/8-bit Resolution
0.5 LSB Integral Non-linearity
± 2 LSB Absolute Accuracy
65 - 260 µs Conversion Time
Up to 15 kSPS at Maximum Resolution
Twelve Multiplexed Single-Ended Input Channels
One Differential amplifier providing gain of 1x - 10x - 40x - 200x
Temperature sensor
Optional Left Adjustment for ADC Result Readout
0 - V
Selectable 2.56 V 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
CC
ADC Input Voltage Range
CC
. See the paragraph
“ADC Noise Canceler” on page 301
CC
are provided On-chip. The voltage refer-
CC
. AV
CC
ATmega16/32U4
must not differ more than ±
on how to connect this
Figure
24-1.
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