ATxmega32D4 Atmel Corporation, ATxmega32D4 Datasheet - Page 231

• Manufacturer Part Number: ATxmega32D4
• Manufacturer: Atmel Corporation

Specifications of ATxmega32D4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 34
• Ext Interrupts: 34
• Usb Speed: No
• Usb Interface: No
• Spi: 4
• Twi (i2c): 2
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 12
• Adc Speed (ksps): 200
• Analog Comparators: 2
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 4
• Eeprom (bytes): 1024
• 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: 4
• Output Compare Channels: 14
• Input Capture Channels: 14
• Pwm Channels: 14
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

20.6
20.7
20.8
20.8.1
8210B–AVR–04/10
Compare function
Starting a conversion
ADC Clock and Conversion Timing
Single conversion without gain
The ADC has a built in 12-bit compare function. The ADC compare register can hold a 12-bit
value that represent an analog threshold voltage. The ADC can be configured to automatically
compare its result with this 12-bit compare value to give an interrupt or event only when the
result is above or below the threshold.
Before a conversion is started, the desired input source must be selected for the ADC. An ADC
conversion can either be started by the application software writing to the start conversion bit, or
from any of the events in the Event System.
The ADC is clocked from the Peripheral Clock. The ADC can prescale the Peripheral Clock to
provide an ADC Clock (Clk
Figure 20-12. ADC Prescaler
The maximum ADC sample rate is given by the ADC clock frequency (f
ple a new measurement once the previous conversion is done. The propagation delay of an
ADC measurement is given by:
RES is the resolution, 8- or 12-bit. The propagation delay will increase by one, two or three extra
ADC clock cycles if the Gain Stage (GAIN) is used, according to the following gain settings:
Figure 20-13 on page 232
ing of the start conversion bit, or the event triggering the conversion (START), must occur
minimum one peripheral clock cycles before the ADC clock cycle where the conversion actually
start (indicated with the grey slope of the START trigger).
Propagation Delay =
• GAIN = 1 for 2x and 4x gain settings
• GAIN = 2 for 8x and 16x gain settings
• GAIN = 3 for 32x and 64x gain settings
1
----------------------------------------- -
+
RES
---------- -
2
PRESCALER[2:0]
f
ADC
ADC
shows the ADC timing for a single conversion without gain. The writ-
+
Clk
GAIN
) that is within the minimum and maximum frequency for the ADC.
PER
9-bit ADC Prescaler
Clk
ADC
ADC
). The ADC can sam-
XMEGA D
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