ATxmega64A4U Atmel Corporation, ATxmega64A4U Datasheet - Page 132

• Manufacturer Part Number: ATxmega64A4U
• Manufacturer: Atmel Corporation

Specifications of ATxmega64A4U

• Flash (kbytes): 64 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 34
• Ext Interrupts: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• 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): 2048
• 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. Interrupts and Programmable Multilevel Interrupt Controller
12.1
12.2
12.3
8331A–AVR–07/11
Features
Overview
Operation
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Interrupts signal a change of state in peripherals, and this can be used to alter program execu-
tion. Peripherals can have one or more interrupts, and all are individually enabled and
configured. When an interrupt is enabled and configured, it will generate an interrupt request
when the interrupt condition is present. The programmable multilevel interrupt controller (PMIC)
controls the handling and prioritizing of interrupt requests. When an interrupt request is acknowl-
edged by the PMIC, the program counter is set to point to the interrupt vector, and the interrupt
handler can be executed.
All peripherals can select between three different priority levels for their interrupts: low, medium,
and high. Interrupts are prioritized according to their level and their interrupt vector address.
Medium-level interrupts will interrupt low-level interrupt handlers. High-level interrupts will inter-
rupt both medium- and low-level interrupt handlers. Within each level, the interrupt priority is
decided from the interrupt vector address, where the lowest interrupt vector address has the
highest interrupt priority. Low-level interrupts have an optional round-robin scheduling scheme to
ensure that all interrupts are serviced within a certain amount of time.
Non-maskable interrupts (NMI) are also supported, and can be used for system critical
functions.
If a boot loader is used, it is possible to move the interrupt vectors from the application section to
the boot loader section so interrupts can also be used and executed during self-programming.
Interrupts must be globally enabled for any interrupts to be generated. This is done by setting
the global interrupt enable ( I ) bit in the CPU status register. The I bit will not be cleared when an
interrupt is acknowledged. Each interrupt level must also be enabled before interrupts with the
corresponding level can be generated.
When an interrupt is enabled and the interrupt condition is present, the PMIC will receive the
interrupt request. Based on the interrupt level and interrupt priority of any ongoing interrupts, the
interrupt is either acknowledged or kept pending until it has priority. When the interrupt request
is acknowledged, the program counter is updated to point to the interrupt vector. The interrupt
vector is normally a jump to the interrupt handler; the software routine that handles the interrupt.
After returning from the interrupt handler, program execution continues from where it was before
the interrupt occurred. One instruction is always executed before any pending interrupt is
served.
Short and predictable interrupt response time
Separate interrupt configuration and vector address for each interrupt
Programmable multilevel interrupt controller
Interrupt vectors can be moved from the application section to the boot loader section
– Interrupt prioritizing according to level and vector address
– Three selectable interrupt levels for all interrupts: low, medium and high
– Selectable, round-robin priority scheme within low-level interrupts
– Non-maskable interrupts for critical functions
Atmel AVR XMEGA AU
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