Power Supply Supervisor; Power-On Reset (Por) / Power-Down Reset (Pdr) / Brown-Out Reset (Bor); Reset; Figure 2. Por, Pdr, And Bor Thresholds - ST STM32C0 Series Getting Started

1.2

Power supply supervisor

1.2.1

Power-on reset (POR) / power-down reset (PDR) / brown-out reset (BOR)

The devices feature an integrated power-on reset (POR) / power-down reset (PDR), coupled with a brown-out
reset (BOR) circuitry. The POR/PDR is active in all power modes.
The BOR can be enabled or disabled only through option bytes. It is not available in Shutdown mode.
When the BOR is enabled, four BOR levels can be selected through option bytes, with independent configuration
for rising and falling thresholds. During power-on, the BOR keeps the device under reset until the V
voltage reaches the specified BOR rising threshold (V
system can start.
During power-down, when V
reset again.
Note: It is not allowed to configure BOR falling threshold (V
(V ).
BORRx
Reset with BOR off
Reset with BOR on
(V
Note: The reset temporization t
of the BOR option bits.
For more details on the brown-out reset thresholds, refer to the electrical characteristics section in the
corresponding datasheet.
1.3

Reset

This section describes the three types of reset on microcontrollers of the STM32C0 series, namely power reset,
system reset and RTC domain reset.
AN5673 - Rev 2
drops below the selected BOR falling threshold (V
DD
Figure 2.
V
DD
V
BORR4
V
BORF4
V
BORR3
V
BORF3
V
BORR2
V
BORF2
V
BORR1
V
BORF1
V
POR
V
PDR
t
RSTTEMPO
t
RSTTEMPO
V )
BORR4 BORF1
POR/BOR rising thresholds
PDR/BOR falling thresholds
starts when V
RSTTEMPO
). At this point, the device reset is released and the
BORRx
) to a value higher than BOR rising threshold
BORFx
POR, PDR, and BOR thresholds
crosses V threshold, indifferently from the configuration
DD POR
AN5673
Power supply supervisor
supply
DD
), the device is put under
BORFx
t
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