Samsung SC32442B54, User Manual

Page: 430 / 647

SC32442B RISC MICROPROCESSOR REAL TIME CLOCK
17-3
ALARM FUNCTION
The RTC generates an alarm signal at a specified time in the power-off mode or normal operation mode. In
normal operation mode, the alarm interrupt (INT_RTC) is activated. In the power-off mode, the power
management wakeup (PMWKUP) signal is activated as well as the INT_RTC. The RTC alarm register (RTCALM)
determines the alarm enable/disable status and the condition of the alarm time setting.
TICK TIME INTERRUPT
The RTC tick time is used for interrupt request. The TICCNT/TICCNT2 register has an interrupt enable bit and the
count value for the interrupt. The count value reaches '0' when the tick time interrupt occurs. Then the period of
interrupt is as follows:
TICCNT : fixed Period = n / 128 second
n: Tick time count value (1~127)
TICCNT2 : selectable by TICCNT2CLK
n: Tick time count value (1~65535)
TICKCNT2CLK TICKCNT2 Frequency
TICK Clock range
(s)
Resolution (ms)
3’b000 32768 (2^15) 0 ~ 2 0.03
3’b001 16384 (2^14) 0 ~ 4 0.06
3’b010 8192 (2^13) 0 ~ 8 0.12
3’b011 4096 (2^12) 0 ~ 16 0.24
3’b100 2048 (2^11) 0 ~ 32 0.49
This RTC time tick may be used for real time operating system (RTOS) kernel time tick. If time tick is generated
by the RTC time tick, the time related function of RTOS will always synchronized in real time.
32.768KHZ X-TAL CONNECTION EXAMPLE
The Figure 17-2 shows a circuit of the RTC unit oscillation at 32.768Khz.
XTIrtc
XTOrtc
32768Hz
15~ 22pF
Figure 17-2. Main Oscillator Circuit Example