ATXMEGA128A4U-AU Datasheet, PDF (47/121 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA A4U Microcontroller

XMEGA A4U
28. DAC - 12-bit Digital to Analog Converter
28.1 Features
28.2 Overview
• One Digital to Analog Converter (DAC)
• 12-bit resolution
• Two independents and continues-time channels per DAC
• Up to 1Million Samples Per Second conversion rate per DAC channel
• Built in calibration that removes
– Offset error
– Gain error
• Multiple conversion trigger sources
– On new available data
– Events from the Event System
• High drive capabilities and support for
– Resistive load
– Capacitive load
– Combined resistive and capacitive load
• 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
The Digital to Analog Converter (DAC) converts digital values to voltages. The 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
DMA req
(Data Empty)
CH0DATA ¹²
AVCC
Internal 1.00V
AREFA
AREFB
Reference
selection
D
A
T
DAC0
A
Output
Driver
Trigger
Select
CTRLB
Trigger
Select
Enable
CTRLA
Enable
Int.
driver
Internal Output
enable
To
AC/ADC
DMA req
(Data Empty)
CH1DATA ¹²
D
A
T
DAC1
A
Output
Driver
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 has one DAC. Notation of this peripheral is DACB.
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8387A–AVR–07/11