ATxmega16A4 Atmel Corporation, ATxmega16A4 Datasheet - Page 126

• 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

12.6.2
8077H–AVR–12/09
Round-robin scheduling
Figure 12-1. Static priority.
To avoid the possible starvation problem for low level interrupts with static priority, the PMIC
gives the possibility for round-robin scheduling for low level interrupts. When round-robin sched-
uling is enabled, the interrupt vector address for the last acknowledged low level interrupt will
have the lowest priority next time one or more interrupts from the low level is requested.
Figure 12-2. Round-robin scheduling.
IV EC x las t ack now le dge d
inte rrupt
IV EC x+1
IV EC N
IV EC 0
IV EC x
:
:
:
:
:
:
Lowes t Addres s
Highes t Addres s
Low est Priority
Highest Priority
IVEC x+1
IVEC N
IVEC 0
IVEC x
:
:
:
:
:
:
IV EC x+1 las t ack now le dge d
inte rrupt
IV EC x+1
IV EC x+2
IV EC N
IV EC 0
IV EC x
Highes t Priority
Lowes t Priority
:
:
:
:
:
:
Low est Priority
Highest Priority
XMEGA A
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