Samsung 8-Bit CMOS Microcontroller Microcassette Recorder User Manual


 
S3C9228/P9228 CLOCK CIRCUITS
7-5
OSCILLATOR CONTROL REGISTER (OSCCON)
The oscillator control register, OSCCON, is located in address D3H. It is read/write addressable and has the
following functions:
System clock selection
Main oscillator control
Sub oscillator control
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)
D3H, R/W
.7 .6 .5 .4 .3 .2 .1 .0MSB LSB
Not used for S3C9228
Main oscillator control bit:
0 = Main oscillator RUN
1 = Main oscillator STOP
Sub oscillator control bit:
0 = Sub oscillator RUN
1 = Sub oscillator STOP
Not used for S3C9228
System clock selection bit:
0 = Main oscillator select
1 = Sub oscillator select
Figure 7-8. Oscillator Control Register (OSCCON)