SAM4C_14 Datasheet, PDF (354/1303 Pages) ATMEL Corporation – Atmel | SMART ARM-based Flash MCU

The RTC output (RTCOUT0) has a source driver selected among seven possibilities.
The first selection choice sticks the associated output at 0 (This is the reset value and it can be used at any time to
disable the waveform generation).
Selection choices 1 to 4 respectively select 1 Hz, 32 Hz, 64 Hz and 512 Hz.
32 Hz or 64 Hz can drive, for example, a TN LCD backplane signal while 1 Hz can be used to drive a blinking
character like “:” for basic time display (hour, minute) on TN LCDs.
Selection choice 5 provides a toggling signal when the RTC alarm is reached.
Selection choice 6 provides a copy of the alarm flag, so the associated output is set high (logical 1) when an alarm
occurs and immediately cleared when software clears the alarm interrupt source.
Selection choice 7 provides a 1 Hz periodic high pulse of 15 µs duration that can be used to drive external devices
for power consumption reduction or any other purpose.
PIO line associated to RTC output is automatically selecting these waveforms as soon as RTC_MR corresponding
fields OUT0 differ from 0.
Figure 17-3. Waveform Generation
‘0’
0
1 Hz
1
32 Hz
2
64 Hz
3
512 Hz
4
toggle_alarm
5
flag_alarm
6
pulse
7
RTCOUT0
RTC_MR(OUT0)
alarm match
event 1
flag_alarm
alarm match
event 2
RTC_SCCR(ALRCLR)
RTC_SCCR(ALRCLR)
toggle_alarm
pulse
Thigh
Tperiod
Tperiod
354
SAM4C Series [DATASHEET]
Atmel-11102E-ATARM-SAM4C32-SAM4C16-SAM4C8-Datasheet_06-Oct-14