AT32UC3L0256 Atmel Corporation, AT32UC3L0256 Datasheet - Page 264

• Manufacturer Part Number: AT32UC3L0256
• Manufacturer: Atmel Corporation

Specifications of AT32UC3L0256

• Flash (kbytes): 256 Kbytes
• Pin Count: 48
• Max. Operating Frequency: 50 MHz
• Cpu: 32-bit AVR
• # Of Touch Channels: 17
• Hardware Qtouch Acquisition: Yes
• Max I/o Pins: 36
• Ext Interrupts: 36
• Usb Speed: No
• Usb Interface: No
• Spi: 5
• Twi (i2c): 2
• Uart: 4
• Lin: 4
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 12
• Adc Speed (ksps): 460
• Analog Comparators: 8
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 16
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.62 to 3.6
• Operating Voltage (vcc): 1.62 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 6
• Output Compare Channels: 18
• Input Capture Channels: 12
• Pwm Channels: 35
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

14. Asynchronous Timer (AST)
14.1
14.2
32145A–12/2011
Features
Overview
Rev: 3.1.0.1
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The Asynchronous Timer (AST) enables periodic interrupts and periodic peripheral events, as
well as interrupts and peripheral events at a specified time in the future. The AST consists of a
32-bit prescaler which feeds a 32-bit up-counter. The prescaler can be clocked from five differ-
ent clock sources, including the low-power 32KHz oscillator, which allows the AST to be used as
a real-time timer with a maximum timeout of more than 100 years. Also, the PB clock or a
generic clock can be used for high-speed operation, allowing the AST to be used as a general
timer.
The AST can generate periodic interrupts and peripheral events from output from the prescaler,
as well as alarm interrupts and peripheral events, which can trigger at any counter value. Addi-
tionally, the timer can trigger an overflow interrupt and peripheral event, and be reset on the
occurrence of any alarm. This allows periodic interrupts and peripheral events at very long and
accurate intervals.
To keep track of time during shutdown the AST can run while the rest of the core is powered off.
This will reduce the power consumption when the system is idle. The AST can also wake up the
system from shutdown using either the alarm wakeup, periodic wakeup. or overflow wakeup
mechanisms.
The AST has been designed to meet the system tick and Real Time Clock requirements of most
embedded operating systems.
32-bit counter with 32-bit prescaler
Clocked Source
Operation and wakeup during shutdown
Optional calendar mode supported
Digital prescaler tuning for increased accuracy
Periodic interrupt(s) and peripheral event(s) supported
Alarm interrupt(s) and peripheral event(s) supported
– System RC oscillator (RCSYS)
– 32KHz crystal oscillator (OSC32K)
– PB clock
– Generic clock (GCLK)
– 1KHz clock from 32KHz oscillator
– Optional clear on alarm
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