NXP Semiconductors K32 L2A Series, Reference Manual, Page: 978 / 1379

The system is comprised of a power-on reset (POR) circuit and a LVD circuit with a
user-selectable trip voltage: high (V
LVDH
) or low (V
LVDL
). The trip voltage is selected by
LVDSC1[LVDV]. The LVD is disabled upon entering VLPx, LLS, and VLLSx modes.
Two flags are available to indicate the status of the low-voltage detect system:
• The Low Voltage Detect Flag in the Low Voltage Status and Control 1 Register
(LVDSC1[LVDF]) operates in a level sensitive manner. LVDSC1[LVDF] is set
when the supply voltage falls below the selected trip point (VLVD).
LVDSC1[LVDF] is cleared by writing 1 to LVDSC1[LVDACK], but only if the
internal supply has returned above the trip point; otherwise, LVDSC1[LVDF]
remains set.
• The Low Voltage Warning Flag (LVWF) in the Low Voltage Status and Control 2
Register (LVDSC2[LVWF]) operates in a level sensitive manner. LVDSC2[LVWF]
is set when the supply voltage falls below the selected monitor trip point (VLVW).
LVDSC2[LVWF] is cleared by writing one to LVDSC2[LVWACK], but only if the
internal supply has returned above the trip point; otherwise, LVDSC2[LVWF]
remains set.
37.3.1 LVD reset operation
By setting LVDSC1[LVDRE], the LVD generates a reset upon detection of a low-voltage
condition. The low-voltage detection threshold is determined by LVDSC1[LVDV]. After
an LVD reset occurs, the LVD system holds the MCU in reset until the supply voltage
rises above this threshold. The LVD field in the SRS register of the RCM module
(RCM_SRS[LVD]) is set following an LVD or power-on reset.
37.3.2 LVD interrupt operation
By configuring the LVD circuit for interrupt operation (LVDSC1[LVDIE] set and
LVDSC1[LVDRE] clear), LVDSC1[LVDF] is set and an LVD interrupt request occurs
upon detection of a low voltage condition. LVDSC1[LVDF] is cleared by writing 1 to
LVDSC1[LVDACK].
37.3.3 Low-voltage warning (LVW) interrupt operation
The LVD system that monitors the VDD supply contains a Low-Voltage Warning Flag
(LVWF) in the Low Voltage Detect Status and Control 2 Register to indicate that the
supply voltage is approaching, but is above, the LVD voltage. The LVW also has an
Low-voltage detect (LVD) system
K32 L2A Reference Manual, Rev. 2, 01/2020
978 NXP Semiconductors