mc68hc908sr12 Freescale Semiconductor, Inc, mc68hc908sr12 Datasheet - Page 104

• Manufacturer Part Number: mc68hc908sr12
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Oscillator (OSC)
7.3.1 CGM Reference Clock Selection
Data Sheet
104
OSCSEL1
0
0
1
1
NOTE:
NOTE:
OSCSEL0
0
1
0
1
Address:
The clock generator module (CGM) reference clock (CGMXCLK) is the
reference clock input to the MCU. It is selected by programming two bits
in a FLASH memory location; the mask option register (MOR), at $FF80.
See
On the ROM device, the oscillator is selected by a ROM-mask layer at
factory.
The internal oscillator is a free running oscillator and is available after
each POR or reset. It is turned-off in stop mode by clearing the
STOP_ICLKEN bit in CONFIG2.
Erased:
Reset:
Read:
Write:
Table 7-1. CGMXCLK Clock Selection
5.6 Mask Option Register
CGMXCLK
OSCSEL1 OSCSEL0
RCCLK
XCLK
$FF80
ICLK
Bit 7
—
U
R
1
Figure 7-2. Mask Option Register (MOR)
= Reserved
Oscillator (OSC)
U
6
1
OSC2 Pin
output of
Inverting
X-TAL
f
f
BUS
BUS
—
R
U
5
1
MC68HC908SR12•MC68HC08SR12 — Rev. 5.0
Not used
Internal oscillator generates the CGMXCLK.
RC oscillator generates the CGMXCLK.
Internal oscillator is available after each POR
or reset.
X-tal oscillator generates the CGMXCLK.
Internal oscillator is available after each POR
or reset.
(MOR).
R
U
4
1
R
U
3
1
Comments
Freescale Semiconductor
R
U
2
1
R
U
1
1
Bit 0
R
U
1