MC908AP16CFAE Datasheet, PDF (72/324 Pages) Freescale Semiconductor, Inc – Table of Contents

Oscillator (OSC)
To CGM and others To CGM PLL
CGMXCLK CGMRCLK
To TBM
OSCCLK
MOR
OSCSEL1
OSCSEL0
MUX
X
RC
I
MUX
X
RC
I
CONFIG2
OSCCLK1
OSCCLK0
XCLK
X-TAL OSCILLATOR
RCCLK
RC OSCILLATOR
To SIM
(and COP)
ICLK
INTERNAL OSCILLATOR
BUS CLOCK _{From SIM}
OSC1
OSC2
Figure 5-1. Oscillator Module Block Diagram
5.2.1 CGM Reference Clock Selection
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
$FFCF. See 3.5 Mask Option Register (MOR).
Address: $FFCF
Bit 7
6
5
4
3
2
1
Bit 0
Read:
OSCSEL1 OSCSEL0
R
R
R
R
R
R
Write:
Reset:
Unaffected by reset
Erased: 1
1
1
1
1
1
1
1
R
= Reserved
Figure 5-2. Mask Option Register (MOR)
MC68HC908AP Family Data Sheet, Rev. 4
72
Freescale Semiconductor