PIC18F23K20_10 Datasheet, PDF (294/456 Pages) Microchip Technology – 28/40/44-Pin Flash Microcontrollers with nanoWatt XLP Technology

PIC18F2XK20/4XK20
22.1 Operation
When the HLVD module is enabled, a comparator uses
an internally generated reference voltage as the set
point. The set point is compared with the trip point,
where each node in the resistor divider represents a
trip point voltage. The “trip point” voltage is the voltage
level at which the device detects a high or low-voltage
event, depending on the configuration of the module.
When the supply voltage is equal to the trip point, the
voltage tapped off of the resistor array is equal to the
internal reference voltage generated by the voltage
reference module. The comparator then generates an
interrupt signal by setting the HLVDIF bit.
The trip point voltage is software programmable to any
one of 16 values. The trip point is selected by
programming the HLVDL<3:0> bits of the HLVDCON
register.
The HLVD module has an additional feature that allows
the user to supply the trip voltage to the module from
an external source. This mode is enabled when bits
HLVDL<3:0> are set to ‘1111’. In this state, the
comparator input is multiplexed from the external input
pin, HLVDIN. This gives users flexibility because it
allows them to configure the High/Low-Voltage Detect
interrupt to occur at any voltage in the valid operating
range.
FIGURE 22-1:
HLVD MODULE BLOCK DIAGRAM (WITH EXTERNAL INPUT)
Externally Generated
Trip Point
VDD
HLVDIN
HLVDIN
VDD
HLVDL<3:0>
HLVDCON
Register
HLVDEN
VDIRMAG
Set
HLVDIF
HLVDEN
BOREN
Internal Voltage
Reference
DS41303G-page 294
 2010 Microchip Technology Inc.