ATxmega256A3U Atmel Corporation, ATxmega256A3U Datasheet - Page 48

• Manufacturer Part Number: ATxmega256A3U
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3U

• Flash (kbytes): 256 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 50
• Ext Interrupts: 50
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 10
• Twi (i2c): 2
• Uart: 7
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 4
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 16
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.6 to 3.6
• Operating Voltage (vcc): 1.6 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 7
• Output Compare Channels: 22
• Input Capture Channels: 22
• Pwm Channels: 22
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

29. AC - Analog Comparator
29.1
29.2
8386A–AVR–07/11
Features
Overview
•
•
•
•
•
•
•
•
The Analog Comparator (AC) compares the voltage level on two inputs and gives a digital output
based on this comparison. The Analog Comparator may be configured to give interrupt requests
and/or events upon several different combinations of input change.
Two important properties of the Analog Comparator when it comes to the dynamic behavior, are
hysteresis and propagation delay. Both these parameters may be adjusted in order to find the
optimal operation for each application.
The input section includes analog port pins, several internal signals and a 64-level programma-
ble voltage scaler. The analog comparator output state can also be directly available on a pin for
use by external devices. Using as pair they can also be set in Window mode to monitor a signal
compared to a voltage window instead of a voltage level.
A constant current source can be enabled, and output on a selectable pin. This can be used to
replace for example external resistors used to charge capacitors in capacitive touch sensing
applications.
The Analog Comparators are always grouped in pairs on each port. They have identical behav-
ior but separate control registers.
PORTA and PORTB each has one AC pair. Notations are ACA and ACB, respectively.
Four Analog Comparators
Selectable propagation delay vs current consumption
Selectable hysteresis
Analog Comparator output available on pin
Flexible Input Selection
Interrupt and event generation on
Window function interrupt and event generation on
Constant current source with configurable output pin selection
– No
– Small
– Large
– All pins on the port
– Output from the DAC
– Bandgap reference voltage.
– A 64-level programmable voltage scaler of the internal VCC voltage
– Rising edge
– Falling edge
– Toggle
– Signal above window
– Signal inside window
– Signal below window
XMEGA A3U
48