SN32F760 Series
32-Bit Cortex-M0 Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 47
Version 2.0
3.2 SYSTEM CLOCK
Different clock sources can be used to drive the system clock (SYSCLK):
12 MHz internal high speed RC (IHRC)
32 KHz internal low speed RC (ILRC)
PLL clock
High speed external (EHS) crystal clock
Low speed external (ELS) 32.768 KHz crystal
Each clock source can be switched on or off independently when it is not used, to optimize power consumption.
The micro-controller is a dual clock system. There are high-speed clock and low-speed clock. The high-speed clock is
generated from the external oscillator & on-chip PLL circuit. The low-speed clock is generated from on-chip low-speed
RC oscillator circuit (ILRC 16 KHz).
3.2.1
INTERNAL RC CLOCK SOURCE
3.2.1.1
Internal High-speed RC Oscillator (IHRC)
The internal high-speed oscillator is 12MHz RC type. The accuracy is ±2% under commercial condition.
The IHRC can be switched on and off using the IHRCEN bit in
Analog Block Control register (SYS0_ANBCTRL)
3.2.1.2
Internal Low-speed RC Oscillator (ILRC)
The system low clock source is the internal low-speed oscillator built in the micro-controller. The low-speed oscillator
uses RC type oscillator circuit. The frequency is affected by the voltage and temperature of the system. In common
condition, the frequency of the RC oscillator is about 32 KHz.
Note: The ILRC can ONLY be switched on and off by HW.
