SAM3U2C Atmel Corporation, SAM3U2C Datasheet - Page 56

• Manufacturer Part Number: SAM3U2C
• Manufacturer: Atmel Corporation

Specifications of SAM3U2C

• Flash (kbytes): 128 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 96 MHz
• Cpu: Cortex-M3
• # Of Touch Channels: 28
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 57
• Ext Interrupts: 57
• Usb Transceiver: 1
• Quadrature Decoder Channels: 1
• Usb Speed: Hi-Speed
• Usb Interface: Device
• Spi: 4
• Twi (i2c): 1
• Uart: 4
• Ssc: 1
• Sd / Emmc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 12
• Adc Speed (ksps): 384
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 36
• Self Program Memory: YES
• External Bus Interface: 1
• Dram Memory: No
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 1.62 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 3
• Output Compare Channels: 3
• Input Capture Channels: 3
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

13.3.1.4
13.3.2
56
SAM3U Series
Stacks
Privileged
Unprivileged software executes at the unprivileged level.
The software can use all the instructions and has access to all resources.
Privileged software executes at the privileged level.
In Thread mode, the CONTROL register controls whether software execution is privileged or
unprivileged, see
always privileged.
Only privileged software can write to the CONTROL register to change the privilege level for
software execution in Thread mode. Unprivileged software can use the SVC instruction to make
a supervisor call to transfer control to privileged software.
The processor uses a full descending stack. This means the stack pointer indicates the last
stacked item on the stack memory. When the processor pushes a new item onto the stack, it
decrements the stack pointer and then writes the item to the new memory location. The proces-
sor implements two stacks, the main stack and the process stack, with independent copies of
the stack pointer, see
In Thread mode, the CONTROL register controls whether the processor uses the main stack or
the process stack, see
uses the main stack. The options for processor operations are:
Table 13-1.
1.
Processor
mode
Thread
Handler
• cannot access the system timer, NVIC, or system control block
• might have restricted access to memory or peripherals.
See
“CONTROL register” on page
Summary of processor mode, execution privilege level, and stack use options
Used to
execute
Applications
Exception
handlers
“CONTROL register” on page
“Stack Pointer” on page
“CONTROL register” on page
Privilege level for
software execution
Privileged or
unprivileged
Always privileged
65.
(1)
58.
65. In Handler mode, software execution is
65. In Handler mode, the processor always
Stack used
Main stack or process
stack
Main stack
(1)
6430E–ATARM–29-Aug-11