ATxmega256A3B Atmel Corporation, ATxmega256A3B Datasheet - Page 291

• Manufacturer Part Number: ATxmega256A3B
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3B

• 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 Speed: No
• Usb Interface: No
• 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

25.3.1
25.3.2
8077H–AVR–12/09
Differential input
Differential input with gain
When differential input is selected all analog input pins can be selected as positive input, and
analog input pins 0 to 3 can be selected as negative input. The ADC must be set in signed mode
when differential input is used.
Figure 25-2. Differential measurement without gain
When differential input with gain is selected all analog input pins can be selected as positive
input, and analog input pins 4 to 7 can be selected as negative input. When the gain stage is
used, the differential analog input is first sampled and amplified by the gain stage before the
result is fed into the ADC. The ADC must be set in signed mode when differential input with gain
is used.
The gain is selectable to 1x, 2x, 4x, 8x, 16x, 32x and 64x gain.
Figure 25-3. Differential measurement with gain
ADC0
ADC1
ADC2
ADC3
ADC4
ADC5
ADC6
ADC7
ADC4
ADC5
ADC6
ADC7
ADC0
ADC1
ADC2
ADC3
ADC4
ADC5
ADC6
ADC7
ADC0
ADC1
ADC2
ADC3
1-64 X
+
-
ADC
+
-
ADC
XMEGA A
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