ATxmega16A4 Atmel Corporation, ATxmega16A4 Datasheet - Page 190

• Manufacturer Part Number: ATxmega16A4
• Manufacturer: Atmel Corporation

Specifications of ATxmega16A4

• Flash (kbytes): 16 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): 3.3
• 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

17. RTC - Real Time Counter
17.1
17.2
8077H–AVR–12/09
Features
Overview
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The Real Time Counter (RTC) is a 16-bit counter, counting reference clock cycles and giving an
event and/or an interrupt request when it reaches a configurable compare and/or top value. The
reference clock is typically generated from a high accuracy crystal of 32.768 kHz, and the design
is optimized for low power consumption. The RTC typically operate in low power sleep modes,
keeping track of time and waking up the device at regular intervals.
The RTC reference clock may be taken from an 32.768 kHz or 1.024 kHz input. Both an external
32.768 kHz crystal oscillator or the 32 kHz internal RC oscillator can be selected as clock
source. For details on reference clock selection to the RTC refer to
Register” on page 86
scale down the reference clock before it reaches the Counter.
The RTC can generate both compare and overflow interrupt request and/or events.
Figure 17-1. Real Time Counter overview.
16-bit resolution
Selectable clock reference
Programmable prescaler
1 Compare register
1 Period register
Clear Timer on overflow
Optional Interrupt/ Event on overflow and compare match
– 32.768 kHz
– 1.024 kHz
in the Clock System section. The RTC has a programmable prescaler to
1.024 kHz
32.768 kHz
prescaler
10-bit
16-bit Counter
=
=
16-bit Compare
16-bit Period
Overflow
Compare Match
”RTCCTRL - RTC Control
XMEGA A
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