Samsung C8278X ユーザーズマニュアル

The oscillator control register, OSCCON, is located in set 1, bank 0, at address E0H. It is read/write addressable 
and has the following functions: 

•  System clock selection 
•  Main oscillator control 
•  Sub oscillator control 
•  Sub oscillator circuit selection 

OSCCON.0 register settings select Main clock or Sub clock as system clock.   
After a reset, Main clock is selected for system clock because the reset value of OSCCON.0 is "0". 

The main oscillator can be stopped or run by setting OSCCON.3. 

The sub oscillator can be stopped or run by setting OSCCON.2. 

 

Oscillator Control Register (OSCCON)

E0H, Set 1, Bank 0, R/W

LSB

MSB

.7

.6

.5

.4

.3

.2

.1

.0

Not used for S3C8275X/

C8278X/C8274X

System clock selection bit:
0 = Main oscillator select
1 = Sub oscillator select

Sub oscillator control bit:
0 = Sub oscillator RUN
1 = Sub oscillator STOP

Main oscillator control bit:
0 = Main oscillator RUN
1 = Main oscillator STOP

Not used for S3C8275X/C8278X/C8274X

Sub oscillator circuit selection bit:
0 = Initial state
1 = Power saving circuit for sub oscillator
      (Automatically cleared to "0" when the sub
      oscillator is stopped by OSCCON.2)

NOTES:
1.  The OSCCON.7 must be maintained to "1", during
     the suboscillator operation.
2. A capacitor (0.1uF) should be connected between
    VREG and GND.