SN8P1700
8-bit micro-controller build-in 12-bit ADC
EXTERNAL HIGH-SPEED OSCILLATOR
SN8P1700 can be operated in four different oscillator modes. There are external RC oscillator modes, high
crystal/resonator mode (12M code option), standard crystal/resonator mode (4M code option) and low crystal mode
(32K code option). For different application, the users can select one of satiable oscillator mode by programming code
option to generate system high-speed clock source after reset.
ꢃExample: Stop external high-speed oscillator.
B0BSET
B0BSET
FSTPHX
FCPUM0
; To stop external high-speed oscillator only.
; To stop external high-speed oscillator and internal low-speed
; oscillator called power down mode (sleep mode).
OSCILLATOR MODE CODE OPTION
SN8P1700 has four oscillator modes for different applications. These modes are 4M, 12M, 32K and RC. The main
purpose is to support different oscillator types and frequencies. High-speed crystal needs more current but the low one
doesn’t. For crystals, there are three steps to select. If the oscillator is RC type, to select “RC” and the system will
divide the frequency by 2 automatically. User can select oscillator mode from Code Option table before compiling. The
table is as follow.
Code Option
Oscillator Mode
Remark
Output the Fcpu square wave from Xout pin.
32768Hz
RC mode
32K
00
01
10
11
12M
4M
12MHz ~ 16MHz
3.58MHz
OSCILLATOR DEVIDE BY 2 CODE OPTION
SN8P1700 has an external clock divide by 2 function. It is a code option called “High_Clk / 2”. If “High_Clk / 2” is
enabled, the external clock frequency is divided by 8 for the Fcpu. Fcpu is equal to Fosc/8. If “High_Clk / 2” is disabled,
the external clock frequency is divided by 4 for the Fcpu. The Fcpu is equal to Fosc/4.
ꢂ
Note: In RC mode, “High_Clk / 2” is always enabled.
OSCILLATOR SAFE GUARD CODE OPTION
SN8P1700 builds in an oscillator safe guard (OSG) to make oscillator more stable. It is a low-pass filter circuit and
stops high frequency noise into system from external oscillator circuit. This function makes system to work better under
AC noisy conditions.
SONiX TECHNOLOGY CO., LTD
Page 60
Revision 1.94
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