SN8P275X Series
8-bit micro-controller build-in 12-bit ADC
SONiX TECHNOLOGY CO., LTD
Page 54
Version 0.7
4.4 SYSTEM HIGH CLOCK
The system high clock is from internal 16MHz oscillator RC type or external oscillator. The high clock type is controlled
by “High_Clk” code option.
High_Clk Code Option
Description
IHRC_16M
The high clock is internal 16MHz oscillator RC type. XIN and XOUT pins are general
purpose I/O pins.
IHRC_RTC
The high clock is internal 16MHz oscillator RC type. XIN and XOUT pins connect
with 32768Hz crystal for RTC clock source.
RC
The high clock is external RC type oscillator. XOUT pin is general purpose I/O pin.
32K
The high clock is external 32768Hz low speed oscillator.
12M
The high clock is external high speed oscillator. The typical frequency is 12MHz.
4M
The high clock is external oscillator. The typical frequency is 4MHz.
4.4.1 INTERNAL HIGH RC
The chip is built-in RC type internal high clock (16MHz) controlled by “IHRC_16M” or “IHRC_RTC” code options. In
“IHRC_16M” mode, the system clock is from internal 16MHz RC type oscillator and XIN / XOUT pins are
general-purpose I/O pins. In “IHRC_RTC” mode, the system clock is from internal 16MHz RC type oscillator and XIN /
XOUT pins are connected with external 32768 crystal for real time clock (RTC).
z
IHRC:
High clock is internal 16MHz oscillator RC type. XIN/XOUT pins are general purpose I/O pins.
z
IHRC_RTC:
High clock is internal 16MHz oscillator RC type. XIN/XOUT pins are connected with external
32768Hz crystal/ceramic oscillator for RTC clock source.
The RTC period is controlled by OPTION register and RTC timer is T0. Please consult “T0 Timer” chapter to apply
RTC function.
4.4.2 EXTERNAL HIGH CLOCK
External high clock includes three modules (Crystal/Ceramic, RC and external clock signal). The high clock oscillator
module is controlled by High_Clk code option. The start up time of crystal/ceramic and RC type oscillator is different.
RC type oscillator’s start-up time is very short, but the crystal’s is longer. The oscillator start-up time decides reset time
length.
RC
4MHz Ceramic
4MHz Crystal
32768Hz Crystal
