
190
XMEGA A [MANUAL]
8077I–AVR–11/2012
17.3
Register Descriptions
17.3.1 CTRL – Control register
Bit 7:3 – 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 2:0 – PRESCALER[2:0]: Clock Prescaling factor
Table 17-1. Real-time counter clock prescaling factor.
17.3.2 STATUS – Status register
Bit 7:1 – 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 0 – SYNCBUSY: Synchronization Busy Flag
This flag is set when the CNT, CTRL, PER, or COMP register is busy synchronizing between the RTC clock and system
clock domains. THis flag is automatically cleared when the synchronisation is complete.
17.3.3 INTCTRL – Interrupt Control register
Bit
7
65
4
3
2
10
+0x00
–
PRESCALER[2:0]
Read/Write
R
RRRR
R/W
Initial Value
0
PRESCALER[2:0]
Group configuration
RTC clock prescaling
000
OFF
No clock source, RTC stopped
001
DIV1
RTC clock / 1 (no prescaling)
010
DIV2
RTC clock / 2
011
DIV8
RTC clock / 8
100
DIV16
RTC clock / 16
101
DIV64
RTC clock / 64
110
DIV256
RTC clock / 256
111
DIV1024
RTC clock / 1024
Bit
7
654
321
0
+0x01
–
SYNCBUSY
Read/Write
RRRR
RRR
R
Initial Value
0
Bit
7
65
43
21
0
+0x02
–
COMPINTLVL[1:0]
OVFINTLVL[1:0]
Read/Write
R
R/W
Initial Value
0