LAPIS Semiconductor ML62Q1000 Series User Manual page 266

Figure 6-6 describes backup mode waveforms at the start of the low-speed crystal clock and in the STOP/STOP-D mode.
The low-speed crystal oscillation circuit operates when choosing it through the low-speed clock mode register (FLMOD)
following the start of low-speed RC oscillation circuit operation after the power supply is turned on. Since the FLMOD
register is only initialized by the POR (power-on reset), the oscillation will continue even if a reset other than POR
occurs after choosing the low-speed crystal.
When choosing the external low-speed oscillation circuit through the FLMOD register, The state on the LSI transfers to
the backup mode and the internal low-speed RC oscillation clock is supplied until the low-speed crystal oscillation starts.
Then, after waiting for the low-speed crystal oscillation start time (T
time (8192 counts), the clock backup interrupt (CBUINT) occurs if the low-speed crystal properly started up. At this
point, release the backup mode. Once the backup mode is released, the crystal oscillation clock is supplied to the
low-speed clock (LSCLK).
In addition, the low-speed crystal oscillation circuit stops oscillation when entering the STOP/STOP-D mode. It resumes
the oscillation by releasing the STOP/STOP-D mode due to external interrupts and etc.. As it transfers to the backup
mode after releasing the STOP/STOP-D mode, release the backup mode following the aforementioned same procedure.
See Chapter 4 "Power Management" for the STOP/STOP-D mode.
See the data sheet for the low-speed oscillation start time (T
Power supply
V
DD
POR
(power-on
reset)
Low-speed RC
oscillation
waveform
Low-speed
clock
Clock backup
interrupt
(CBUINT)
STOP/STOP-D
mode
LOSCS
LOSCB
FEUL62Q1000
T : RC oscillation start time
RCL
RC oscillation waveform
512 counts (approx. 16 ms)
CPU operation start
RC oscillation
waveform
SFR setting
T : Crystal oscillation
XTL
start time
Crystal oscillation waveform
8192 counts (approx.
250 ms)
CBUINT does not
occur at these timing
Write "1"
Figure 6-6 Low-speed Crystal Oscillation Circuit Operation
(When Low-speed Crystal Starting Up, in STOP/STOP-D Mode)
Chapter 6 Clock Generation Circuit
) and low-speed crystal oscillation stabilization
XTL
).
XTL
T
RCL
RC oscillation waveform
Crystal
oscillation
waveform
T
XTL
External interrupt occurred
ML62Q1000 Series User's Manual
: RC oscillation start time
10 counts (approx. 320 μs)
CPU operation start
RC Crystal oscillation
waveform
oscillation
waveform
: Crystal oscillation start time
Crystal oscillation waveform
8192 counts (approx.
250 ms)
Write "1"
6-18