at32uc3b0512-z2ues ATMEL Corporation, at32uc3b0512-z2ues Datasheet - Page 34

• Manufacturer Part Number: at32uc3b0512-z2ues
• Description: 32-bit Avr Microcontroller
• Manufacturer: ATMEL Corporation

8. Boot Sequence
8.1
8.2
32059J–12/2010
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.
AT32UC3B
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