AT32UC3A464S Atmel Corporation, AT32UC3A464S Datasheet - Page 64

• Manufacturer Part Number: AT32UC3A464S
• Manufacturer: Atmel Corporation

Specifications of AT32UC3A464S

• Flash (kbytes): 64 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 66 MHz
• Cpu: 32-bit AVR
• Hardware Qtouch Acquisition: No
• Usb Transceiver: 1
• Usb Speed: Hi-Speed
• Usb Interface: Device + OTG
• Spi: 6
• Twi (i2c): 2
• Uart: 4
• Ssc: 1
• Sd / Emmc: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: AES
• Sram (kbytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.0 to 3.6
• Operating Voltage (vcc): 3.0 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

8.1.2
8.1.3
8.2
8.2.1
64
Event handling in AVR32B
AVR32
Supervisor calls
Debug requests
Exceptions and interrupt requests
The execution of the event handler routine then continues from the effective address calculated.
The rete instruction signals the end of the event. When encountered, the Return Status Register
and Return Address Register are popped from the system stack and restored to the Status Reg-
ister and Program Counter. If the rete instruction returns from INT0, INT1, INT2 or INT3,
registers R8 to R12 and LR are also popped from the system stack. The restored Status Regis-
ter contains information allowing the core to resume operation in the previous execution mode.
This concludes the event handling.
The AVR32 instruction set provides a supervisor mode call instruction. The scall instruction is
designed so that privileged routines can be called from any context. This facilitates sharing of
code between different execution modes. The scall mechanism is designed so that a minimal
execution cycle overhead is experienced when performing supervisor routine calls from time-
critical event handlers.
The scall instruction behaves differently depending on which mode it is called from. The behav-
iour is detailed in the instruction set reference. In order to allow the scall routine to return to the
correct context, a return from supervisor call instruction, rets, is implemented. In the AVR32A
microarchitecture, scall and rets uses the system stack to store the return address and the sta-
tus register.
The AVR32 architecture defines a dedicated debug mode. When a debug request is received by
the core, Debug mode is entered. Entry into Debug mode can be masked by the DM bit in the
status register. Upon entry into Debug mode, hardware sets the SR[D] bit and jumps to the
Debug Exception handler. By default, debug mode executes in the exception context, but with
dedicated Return Address Register and Return Status Register. These dedicated registers
remove the need for storing this data to the system stack, thereby improving debuggability. The
mode bits in the status register can freely be manipulated in Debug mode, to observe registers
in all contexts, while retaining full privileges.
Debug mode is exited by executing the retd instruction. This returns to the previous context.
When an event other than scall or debug request is received by the core, the following actions
are performed atomically:
3. The Mode bits are set to reflect the priority of the accepted event, and the correct regis-
1. The pending event will not be accepted if it is masked. The I3M, I2M, I1M, I0M, EM and
ing the appropriate bit. Each exception handler has a dedicated handler address, and
this address uniquely identifies the exception source.
ter file bank is selected. The address of the event handler, as shown in Table 8-1, is
loaded into the Program Counter.
GM bits in the Status Register are used to mask different events. Not all events can be
masked. A few critical events (NMI, Unrecoverable Exception, TLB Multiple Hit and Bus
Error) can not be masked. When an event is accepted, hardware automatically sets the
mask bits corresponding to all sources with equal or lower priority. This inhibits accep-
tance of other events of the same or lower priority, except for the critical events listed
above. Software may choose to clear some or all of these bits after saving the neces-
32000D–04/2011