ATxmega256A3U Atmel Corporation, ATxmega256A3U Datasheet - Page 47

• 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

28. DAC - 12-bit Digital to Analog Converter
28.1
28.2
8386A–AVR–07/11
Features
Overview
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The Digital to Analog Converter (DAC) converts digital values to voltages. Each DAC has two
channels, 12-bit resolution, and is capable of converting 1Million Samples Per Second (MSPS)
on each channels. The built-in calibration system can remove offset and gain error when loaded
with calibration values from software.
Figure 28-1. DAC overview
A DAC conversion is automatically started when new data to be converted is available. Event
from the Event System can also be used, and this enable synchronized and timed conversions
between the DAC and other peripherals such as a Timer/Counter. The DMA Controller can be
used to transfer data to the DAC.
The DAC has high drive strengths and is capable of driving both resistive and capacitive loads,
and a load which is a combination of this. A low power mode is available, and this will reduce the
drive strengths of the output. Both internal and external voltage reference can be used. The
DAC output is also internally available for use as input to the Analog Comparator or ADC.
PORTB each has one DAC. Notation of this peripheral is DACB.
One Digital to Analog Converter (DAC)
12-bit resolution
Up to 1Million Samples Per Second conversion rate per DAC channel
Built in calibration that removes
Multiple conversion trigger sources
High drive capabilities and support for
Internal and external reference options
DAC output available as input to Analog Comparator and ADC
Low Power mode with reduced drive strength
Optional DMA transfer of data
– Offset error
– Gain error
– On new available data
– Events from the Event System
– Resistive load
– Capacitive load
– Combined resistive and capacitive load
(Data Empty)
(Data Empty)
DMA req
Internal 1.00V
DMA req
AREFA
AREFB
AVCC
CH0DATA
CH1DATA
Reference
selection
12
12
D
A
T
A
D
A
T
A
Trigger
Trigger
CTRLB
DAC0
DAC1
Select
Select
CTRLA
Enable
Enable
Internal Output
enable
Output
Driver
Int.
driver
Output
Driver
XMEGA A3U
To
AC/ADC
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