SN8P2714X_2715
8-bit micro-controller build-in 12-bit ADC
SONiX TECHNOLOGY CO., LTD
Page 49
V1.4
7.1.1 OSCM REGISTER DESCRIPTION
The OSCM register is an oscillator control register. It can control oscillator select, system mode.
OSCM initial value = xxx0 000x
0CAH
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
OSCM
- - - -
CPUM0
CLKMD
STPHX
-
- - - -
R/W
R/W
R/W
-
Bit [4:3]
CPUM 0:
CPU operating mode control bit.
0 = normal mode
1 = sleep (power down) mode. Always enter normal mode after wakeup.
Bit 2
CLKMD:
Select instruction cycle clock (Fcpu) source
0
Fcpu came form External high clock (Fhosc). Operation mode is normal mode.
1 Fcpu came from Internal low clock (Flosc). Operation mode is slow mode.
Bit1
STPHX
: Stop High clock control bit.
0=High clock free running.
1=High
clock
stop.
7.1.2 EXTERNAL HIGH-SPEED OSCILLATOR
The high clock oscillator of SN8P2710 can be configured as four different oscillator types. There are external RC
oscillator modes, high crystal/resonator mode (12M code option), standard crystal/resonator mode (4M code option).
For different application, the users can select one of suitable oscillator mode by programming “High_Clk” code option
to generate system high-speed clock source after reset.
Â
Example: Stop external high-speed oscillator.
B0BSET
FSTPHX
; To stop external high-speed oscillator only.
B0BSET
FCPUM0
; To stop external high-speed oscillator and internal low-speed
; oscillator called power down mode (sleep mode).
7.1.3 HIGH CLOCK OSCILLATOR CODE OPTION
SN8P2710 provide four oscillator modes for different applications. These modes are 4M, 12M 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. User can select oscillator mode from Code Option table before
compiling. The table is as follow.
Code Option
Content
Function Description
Ext_RC
Low cost external RC oscillator for high clock oscillator.
Output the Fcpu clock from Xout pin.
12M_X’tal High speed crystal /resonator (e.g. 12MHz ~ 16MHz) for high clock oscillator.
High_Clk
4M_X’tal Middle speed crystal /resonator (e.g. 4MHz ~ 10Mhz) for high clock oscillator.