mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 102

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 2 Clocks and Reset Generator (S12CRGV6)
A number greater equal than 4096 rising OSCCLK edges within a check window is called osc ok. Note that
osc ok immediately terminates the current check window. See
The sequence for clock quality check is shown in
102
POR
LVR
check window
Clock OK
num = 50
OSCCLK
active?
osc ok
SCM
?
Clock
yes
no
VCO
FSTWKP = 1
SCME = 1 &
no
?
exit full stop
no
yes
Figure 2-20. Sequence for Clock Quality Check
CM fail
1
1
Figure 2-19. Check Window Example
yes
MC9S12XDP512 Data Sheet, Rev. 2.17
2
2
Switch to OSCCLK
3
num = 0
num=num–1
Exit SCM
num > 0
4
3
?
yes
5
check window
Figure
4095
no
4096
2-20.
Clock Monitor Reset
Enter SCM
Enter SCM
osc ok
Figure 2-19
yes
49999
SCME=1
active?
SCM
as an example.
?
no
yes
FSTWKP = 0
no
yes
50000
?
Freescale Semiconductor
no
num = 0