ST72321
15.3 FLASH REV “S” and ALL ROM DEVICES
15.3.1 External clock source with PLL
External clock source is not supported with the
PLL enabled.
15.3.2 LVD Startup behaviour
When the LVD is enabled, the MCU reaches its
authorized operating voltage from a reset state.
However, in some devices, the reset state is re-
leased when VDD is approximately between 0.8V
and 1.5V. As a consequence, the I/Os may toggle
when VDD is within this window.
This may be an issue especially for applications
where the MCU drives power components.
Because Flash write access is impossible within
this window, the Flash memory contents will not be
corrupted.
Figure 111. LVD Startup Behaviour
5V
VIT+
LVD RESET
1.5V
0.8V
V DD
Window
t
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