ATxmega256A3BU Atmel Corporation, ATxmega256A3BU Datasheet - Page 354

• Manufacturer Part Number: ATxmega256A3BU
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3BU

• 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: 47
• Ext Interrupts: 49
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 8
• Twi (i2c): 2
• Uart: 6
• 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

Figure 28-1. ADC overview
28.3
28.3.1
8331A–AVR–07/11
ADC15
ADC0
ADC4
ADC7
ADC0
ADC3
•
•
•
•
•
•
•
•
•
Input sources
Differential input
½x - 64x
Internal
Internal
signals
signals
Both internal and external reference voltages can be used. An integrated temperature sensor is
available for use with the ADC. The output from the DAC, VCC/10 and the Bandgap voltage can
also be measured by the ADC.
The ADC has a compare function for accurate monitoring of user defined thresholds with mini-
mum software intervention required.
CHn.CTRL
CHn.MUXCTRL
CHn.SCAN
Input sources are the voltage inputs that the ADC can measure and convert. Four types of mea-
surements can be selected:
The input pins are used for single ended and differential input, while the internal inputs are
directly available inside the device. In devices with two ADCs, PORTA pins can be input to
ADCA and PORTB pins can be input to ADCB. For XMEGA devices with only one ADC, input
pins may be available for ADCA on both PORTA and PORTB.
The ADC is differential, so for single ended measurements the negative input is connected to an
fixed internal value. The four types of measurements and their corresponding input options are
shown in
When differential input is enabled, all input pins can be selected as positive input, and input pins
0 to 3 can be selected as negative input. The ADC must be in signed mode when differential
input is used.
• Differential input
• Differential input with gain
• Single ended input
• Internal input
Internal VCC/1.6V
V
Internal VCC/2
V
INN
Internal 1.00V
INP
Figure 28-2 on page 355
AREFA
AREFB
V
IN
REFCTRL
ADC
Stage
2
S&H
1
2 bits
ADC
Digital Correction Logic
DAC
CTRLA
CTRLB
Enable
Start
Mode
Resolution
Stage
2
2
Σ
to
2x
Figure 28-6 on page
Stage
2
V
12
EVCTRL
OUT
Action
Select
Atmel AVR XMEGA AU
CH0
CH1
CH2
CH3
Int. Flag
Int. Flag
Int. Flag
Int. Flag
357.
Compare Register
Int. Mode
Int. Mode
Int. Mode
Int. Mode
Result
Result
Result
Result
<
>
Threshold
(Int Req)
354