ATxmega32A4 Atmel Corporation, ATxmega32A4 Datasheet - Page 78

• Manufacturer Part Number: ATxmega32A4
• Manufacturer: Atmel Corporation

Specifications of ATxmega32A4

• 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: 7
• Twi (i2c): 2
• Uart: 5
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 2
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• 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: 5
• Output Compare Channels: 16
• Input Capture Channels: 16
• Pwm Channels: 16
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

7.3.3
7.3.4
7.3.5
7.4
7.4.1
7.4.1.1
7.4.1.2
7.4.1.3
8077H–AVR–12/09
Clock Sources
Peripheral Clock - clk
Peripheral 2x/4x Clocks clk
Asynchronous Clock - clk
Internal Oscillators
32 kHz Ultra Low Power Oscillator
32.768 kHz Calibrated Internal Oscillator
32 MHz Run-time Calibrated Internal Oscillator
The majority of peripherals and system modules use the Peripheral Clock. This includes the
DMA Controller, Event System, Interrupt Controller, External Bus Interface and RAM. This clock
is always synchronous to the CPU Clock but may run even if the CPU Clock is turned off.
Modules that can run at two or four times the CPU Clock frequency can use the Peripheral 2x
and Peripheral 4x clocks.
The Asynchronous Clock allows the Real Time Counter (RTC) to be clocked directly from an
external 32.768 kHz crystal oscillator, or the 32 times prescaled output from the internal
32.768 kHz oscillator or ULP oscillator. The dedicated clock domain allows operation of this
peripheral, even if the device is in sleep mode where the rest of the clocks are stopped.
The clock sources are divided in two main groups: internal oscillators and external clock
sources. Most of the clock sources can be directly enabled and disabled from software, while
others are automatically enabled or disabled dependent on current peripheral settings. After
reset the device starts up running from the 2 MHz internal oscillator. The DFLLs and PLL are
turned off by default.
The internal oscillators do not require any external components to run. For details on character-
istics and accuracy of the internal oscillators refer to the device data sheet.
This oscillator provides an approximate 32 kHz clock. The 32 kHz Ultra Low Power (ULP) Inter-
nal Oscillator is a very low power clock source, and it is not designed for high accuracy.The
oscillator employs a built in prescaler providing both a 32 kHz output and a 1 kHz output. The
oscillator is automatically enabled/disabled when used as clock source for any part of the
device. This oscillator can be selected as clock source for the RTC.
This RC oscillator provides an approximate 32.768 kHz clock. A factory-calibrated value is writ-
ten to the 32.768 kHz oscillator calibration register during reset to ensure that the oscillator is
running within its specification. The calibration register can also be written from software for run-
time calibration of the oscillator frequency. The oscillator employs a built in prescaler providing
both a 32.768 kHz output and a 1.024 kHz output.
This RC oscillator provides an approximate 32 MHz clock. The oscillator employs a Digital Fre-
quency Locked Loop (DFLL) that can be enabled for automatic run-time calibration of the
oscillator. A factory-calibrated value is written to the 32 MHz DFLL Calibration Register during
reset to ensure that the oscillator is running within its specification. The calibration register can
also be written from software for manual run-time calibration of the oscillator.
PER
ASY
PER2
/clk
PER4
XMEGA A
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