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Chapter 8 S12 Clock, Reset and Power Management Unit (S12CPMU_UHV_V6)
MC9S12ZVM Family Reference Manual Rev. 1.3
264
Freescale Semiconductor
Table 8-7. COPOSCSEL1, COPOSCSEL0 clock source select description
1
RTIOSCSEL
RTI Clock Select— RTIOSCSEL selects the clock source to the RTI. Either IRCCLK or OSCCLK. Changing the
RTIOSCSEL bit re-starts the RTI time-out period.
RTIOSCSEL can only be set to 1, if UPOSC=1.
UPOSC= 0 clears the RTIOSCSEL bit.
0 RTI clock source is IRCCLK.
1 RTI clock source is OSCCLK.
0
COP
OSCSEL0
COP Clock Select 0 — COPOSCSEL0 and COPOSCSEL1 combined determine the clock source to the COP
(see also
)
If COPOSCSEL1 = 1, COPOSCSEL0 has no effect regarding clock select and changing the COPOSCSEL0 bit
does not re-start the COP time-out period.
When COPOSCSEL1=0,COPOSCSEL0 selects the clock source to the COP to be either IRCCLK or OSCCLK.
Changing the COPOSCSEL0 bit re-starts the COP time-out period.
COPOSCSEL0 can only be set to 1, if UPOSC=1.
UPOSC= 0 clears the COPOSCSEL0 bit.
0 COP clock source is IRCCLK.
1 COP clock source is OSCCLK
COPOSCSEL1
COPOSCSEL0
COP clock source
0
0
IRCCLK
0
1
OSCCLK
1
x
ACLK
Table 8-6. CPMUCLKS Descriptions (continued)
Field
Description