97
8331B–AVR–03/12
Atmel AVR XMEGA AU
7.10.2
STATUS – Oscillator Status register
• Bit 7:5 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always
write these bits to zero when this register is written.
• Bit 4 – PLLRDY: PLL Ready
This flag is set when the PLL has locked on the selected frequency and is ready to be used as
the system clock source.
• Bit 3 – XOSCRDY: External Clock Source Ready
This flag is set when the external clock source is stable and is ready to be used as the system
clock source.
• Bit 2 – RC32KRDY: 32.768kHz Internal Oscillator Ready
This flag is set when the 32.768kHz internal oscillator is stable and is ready to be used as the
system clock source.
• Bit 1 – RC32MRDY: 32MHz Internal Oscillator Ready
This flag is set when the 32MHz internal oscillator is stable and is ready to be used as the sys-
tem clock source.
• Bit 0 – RC2MRDY: 2MHz Internal Oscillator Ready
This flag is set when the 2MHz internal oscillator is stable and is ready to be used as the system
clock source.
7.10.3
XOSCCTRL – XOSC Control register
• Bit 7:6 – FRQRANGE[1:0]: 0.4 - 16MHz Crystal Oscillator Frequency Range Select
These bits select the frequency range for the connected crystal oscillator according to
Bit
7
6
5
4
3
2
1
0
–
–
–
PLLRDY
XOSCRDY
RC32KRDY
RC32MRDY
RC2MRDY
STATUS
Read/Write
R
R
R
R
R
R
R
R
Initial Value
0
0
0
0
0
0
0
0
Bit
7
6
5
4
3
2
1
0
FRQRANGE[1:0]
X32KLPM
XOSCPWR
XOSCSEL[3:0]
XOSCCTRL
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
