ATxmega64A1 Atmel Corporation, ATxmega64A1 Datasheet - Page 300

• Manufacturer Part Number: ATxmega64A1
• Manufacturer: Atmel Corporation

Specifications of ATxmega64A1

• Flash (kbytes): 64 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 78
• Ext Interrupts: 78
• Usb Speed: No
• Usb Interface: No
• Spi: 12
• Twi (i2c): 4
• Uart: 8
• 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: 4
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 4
• Eeprom (bytes): 2048
• Self Program Memory: YES
• External Bus Interface: 1
• Dram Memory: sdram
• 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: 8
• Output Compare Channels: 24
• Input Capture Channels: 24
• Pwm Channels: 24
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

25.10 ADC Input Model
8077H–AVR–12/09
Figure 25-18. ADC timing for free running mode
An analog voltage input must be able to charge the sample and hold (S/H) capacitor in the ADC
in order to achieve maximum accuracy. Seen externally the ADC input consists of a input chan-
nel (R
300
Figure 25-19. ADC input for single ended measurements
Figure 25-20. ADC input for differential measurements and differential measurements with gain
In order to achieve n bit accuracy, the source output resistance, R
ADC input resistance on a pin:
GAINSTAGE AMPLIFY
START CH0, wo/GAIN
START CH1, wo/GAIN
GAINSTAGE SAMPLE
START CH0, w/GAIN
START CH1, w/GAIN
CONV COMPLETE
Negative
and
Positive
Positive
ADC SAMPLE
input
input
input
channel
CLK
Figure 25-20 on page 300
ADC
) and the switch (R
1
0
2
switch
2
1
R
R
R
3
channel
channel
shows the ADC input channels.
channel
) resistance, and the S/H capacitor.
2
3
2
4
3
3
5
R
R
R
switch
switch
switch
0
6
2
1
7
source
2
, must be less than the
3
2
Figure 25-19 on page
8
C
C
C
Sample
3
Sample
Sample
XMEGA A
3
0
9
VCC/2
VCC/2
0
1
10
300