AT32UC3B0256-A2UR Atmel, AT32UC3B0256-A2UR Datasheet - Page 34

• Manufacturer Part Number: AT32UC3B0256-A2UR
• Description: MCU AVR32 256K FLASH 64-TQFP
• Manufacturer: Atmel
• Series: AVR®32 UC3r

Specifications of AT32UC3B0256-A2UR

• Package / Case: 64-TQFP, 64-VQFP
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Operating Temperature: -40°C ~ 85°C
• Speed: 60MHz
• Number Of I /o: 44
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 32K x 8
• Program Memory Size: 256KB (256K x 8)
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Connectivity: I²C, IrDA, SPI, SSC, UART/USART, USB
• Core Size: 32-Bit
• Package: 64TQFP
• Device Core: AVR32
• Family Name: AT32
• Maximum Speed: 60 MHz
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Number Of Programmable I/os: 44
• Interface Type: I2S/SPI/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Number Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

8. Boot Sequence
8.1
8.2
32059K–03/2011
Starting of clocks
Fetching of initial instructions
This chapter summarizes the boot sequence of the AT32UC3B. The behaviour after power-up is
controlled by the Power Manager. For specific details, refer to section Power Manager (PM).
After power-up, the device will be held in a reset state by the Power-On Reset circuitry, until the
power has stabilized throughout the device. Once the power has stabilized, the device will use
the internal RC Oscillator as clock source.
On system start-up, the PLLs are disabled. All clocks to all modules are running. No clocks have
a divided frequency, all parts of the system recieves a clock with the same frequency as the
internal RC Oscillator.
After reset has been released, the AVR32 UC CPU starts fetching instructions from the reset
address, which is 0x8000_0000. This address points to the first address in the internal Flash.
The code read from the internal Flash is free to configure the system to use for example the
PLLs, to divide the frequency of the clock routed to some of the peripherals, and to gate the
clocks to unused peripherals.
When powering up the device, there may be a delay before the voltage has stabilized, depend-
ing on the rise time of the supply used. The CPU can start executing code as soon as the supply
is above the POR threshold, and before the supply is stable. Before switching to a high-speed
clock source, the user should use the BOD to make sure the VDDCORE is above the minimum
level.
AT32UC3B
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