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Chapter 4
Clock Generator
Preliminary User’s Manual U17566EE1V2UM00
SSCG operating (provided that CGSTAT.CMPLPSM
=
1 before power
save mode request)
– CGSTAT.CMPLPSM = 1 if a power save mode has been completely
entered, wake-up configuration established, PLL/SSCG stopped
(provided that a power save mode request has been accepted before, i.e.
CGSTAT.CMPLPSM
=
1
→
0)
Note that CGSTAT.CMPLPSM is set to 0 if a power save mode request is
accepted. If it was 0 before it does not change it’s state.
Table 4-30
summarizes the different configurations.
Table 4-30
Power save mode wake-up configurations
If the power save mode request was accepted the entire clock generator can
be reconfigured after wake-up. Afterwards set CKC.PLLEN = 1 and
CKC.SCEN = 1 and wait the stabilization times before using the PLL and
SSCG as clock sources.
After IDLE and
STOP
On return from IDLE or STOP mode, the bits PCC.CLS, PCC.CKS1, and
PCC.CKS2 are cleared. After IDLE mode, the main oscillator is still running; on
return from STOP mode, it is automatically started.
As a result, the main oscillator is chosen and enabled as the source for the
CPU system clock VBCLK.
After WATCH
In WATCH mode the main oscillator operation depends on PSM.OSCDIS:
• If PSM.OSCDIS was 0 before entering WATCH mode the main oscillator
remains active. After WATCH mode release the main oscillator is chosen as
the CPU system clock.
• If PSM.OSCDIS was 1 before entering WATCH mode the main oscillator is
stopped during WATCH mode. After WATCH mode release the main
CGSTAT.CMPLPSM
Registers and
clock paths
a
a)
A change of a register’s contents can only be taken as an indicator if it is before
power save mode request different to the wake-up configuration.
Configuration after wake-up
before PSM-RQ
b
b)
PSM-RQ: power save mode request (PSC.STP = 1)
after wake-up
0
0
not changed
PSM-RQ not accepted
changed
PSM-RQ accepted
configuration done, but PLL/
SSCG operating
1
not changed
not possible
changed
PSM-RQ accepted
configuration done, PLL/SSCG
off
1
0
not changed
not possible
changed
PSM-RQ accepted
configuration done, but PLL/
SSCG operating
1
not changed
PSM-RQ not accepted
changed
PSM-RQ accepted
configuration done, PLL/SSCG
off
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