SN8P26L38
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 51
Version 1.5
4.4
OSCM REGISTER
The OSCM register is an oscillator control register. It controls oscillator status, system mode.
0CAH
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
OSCM
0
0
0
CPUM1
CPUM0
CLKMD
STPHX
0
Read/Write
-
-
-
R/W
R/W
R/W
R/W
-
After reset
-
-
-
0
0
0
0
-
Bit 1
STPHX:
External high-speed oscillator control bit.
0 = External high-speed oscillator free run.
1 = External high-speed oscillator free run stop. Internal low-speed RC oscillator is still running.
Bit 2
CLKMD:
System high/Low clock mode control bit.
0 = Normal (dual) mode. System clock is high clock.
1 = Slow mode. System clock is internal low clock.
Bit[4:3]
CPUM[1:0]:
CPU operating mode control bits.
00 = normal.
01 = sleep (power down) mode.
10 = green mode.
11 = reserved.
“STPHX” bit controls internal high speed RC type oscillator and external oscillator operations. When “STPHX=0”, the
external oscillator or internal high speed RC type oscillator active. When
“STPHX=1”, the external oscillator or internal
high speed RC type oscillator are disabled. The STPHX function is depend on different high clock options to do
different controls.
High_CLK = IHRC_8M:
“STPHX=1” disables internal high speed RC type oscillator.
High_CLK = IHRC_RTC:
“STPHX=1” disables internal high speed RC type oscillator and external 32768Hz
crystal.
High_CLK = RC, 4M, 8M, 32K:
“STPHX=1” disables external oscillator.
4.5
SYSTEM HIGH CLOCK
The system high clock is from internal 8MHz oscillator RC type or external oscillator. The high clock type is controlled
by
“High_Clk” code option.
IHRC_8M:
The system clock source is from internal high speed 8MHz RC type oscillator. In the mode, XIN and
XOUT pins are bi-direction GPIO mode, and not to connect any external oscillator.
IHRC_RTC:
The system clock source is from internal high speed 8MHz RC type oscillator, and includes external
low speed 32768Hz crystal for RTC function. The XIN and XOUT pins are defined to drive external 32768Hz
crystal and not GPIO mode.
RC:
The system clock source is from external low cost RC type oscillator. The RC oscillator circuit only connects
to XIN pin, and the XOUT pin is bi-direction GPIO mode.
32K X
’tal:
The system clock source is from external low speed 32768Hz crystal. The option only supports
32768Hz crystal.
8M X
’tal:
The system clock source is from external high speed crystal/resonator. The oscillator bandwidth is
8MHz~16MHz.
4M X
’tal:
The system clock source is from external high speed crystal/resonator. The oscillator bandwidth is
1MHz~10MHz.