Datasheet

66
AT32UC3A
13.5.11.3 External Reset
The external reset detector monitors the state of the RESET_N pin. By default, a low level on
this pin will generate a reset.
13.5.12 Calibration registers
The Power Manager controls the calibration of the RC oscillator, voltage regulator, bandgap
voltage reference through several calibrations registers.
Those calibration registers are loaded after a Power On Reset with default values stored in fac-
tory-programmed flash fuses.
Although it is not recommended to override default factory settings, it is still possible to override
these default values by writing to those registers. To prevent unexpected writes due to software
bugs, write access to these registers is protected by a “key”. First, a write to the register must be
made with the field “KEY” equal to 0x55 then a second write must be issued with the “KEY” field
equal to 0xAA
13.6 User Interface
Offset Register Name Access Reset State
0x0000 Main Clock Control MCCTRL Read/Write 0x00000000
0x0004 Clock Select CKSEL Read/Write 0x00000000
0x0008 CPU Mask CPUMASK Read/Write 0x00000003
0x000C HSB Mask HSBMASK Read/Write 0x0000007F
0x0010 PBA Mask PBAMASK Read/Write 0x0000FFFF
0x0014 PBB Mask PBBMASK Read/Write 0x0000003F
0x0018 - 0x001C Reserved
0x0020 PLL0 Control PLL0 Read/Write 0x00000000
0x0024 PLL1 Control PLL1 Read/Write 0x00000000
0x0028 Oscillator 0 Control Register OSCCTRL0 Read/Write 0x00000000
0x002C Oscillator 1 Control Register OSCCTRL1 Read/Write 0x00000000
0x0030 Oscillator 32 Control Register OSCCTRL32 Read/Write 0x00000000
0x0034 Reserved
0x0038 Reserved
0x003C Reserved
0x0040 PM Interrupt Enable Register IER Write Only 0x00000000
0x0044 PM Interrupt Disable Register IDR Write Only 0x00000000
0x0048 PM Interrupt Mask Register IMR Read Only 0x00000000
0x004C PM Interrupt Status Register ISR Read Only 0x00000000
0x0050 PM Interrupt Clear Register ICR Write Only 0x00000000
0x0054 Power and Oscillators Status Register POSCSR Read/Write 0x00000000
0x0058 - 0x005C Reserved
32058K
AVR32-01/12