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XMEGA A [MANUAL]
8077I–AVR–11/2012
After writing to the high byte of the CNT register, the condition for setting OVFIF and COMPIF, as well as the overflow
and compare match wake-up condition, will be disabled for the following two RTC32 clock cycles.
18.3.6 CNT1 – Counter register 1
18.3.7 CNT2 – Counter register 2
18.3.8 CNT3 – Counter register 3
18.3.9 PER0 – Period register 0
The PER0, PER1, PER2, and PER3 registers represent the 32-bit value, PER. PER is constantly compared with the
counter value (CNT). A compare match will set OVFIF in the INTFLAGS register, and CNT will be set to zero in the next
RTC32 clock cycle. OVFIF will be set on the next count after match.
The PER register can be written only if the RTC32 is disabled and not currently synchronizing; i.e., when both ENABLE
and SYNCBUSY are zero.
After writing a byte in the PER register, the write (HW/SW) condition for setting OVFIF and the overflow wake-up
condition are disabled for the following two RTC32 clock cycles.
Bit
7
6
5
4
3
2
1
0
+0x04
CNT[7:0]
Read/Write
R/W
Initial Value
0
Bit
7
6
5
432
1
0
+0x05
CNT[15:8]
Read/Write
R/W
Initial Value
0
Bit
7
6
5
4
3
2
1
0
+0x06
CNT[23:16]
Read/Write
R/W
Initial Value
0
Bit
7
6
5
4
3
2
1
0
+0x07
CNT[31:24]
Read/Write
R/W
Reset Value
0
Bit
7
6
5
4
3
2
1
0
+0x08
PER[7:0]
Read/Write
R/W
Initial Value
0