Microchip Technology MA160014 Data Sheet

 2010-2012 Microchip Technology Inc.

DS41412F-page 349

The PIC18(L)F2X/4XK22 devices have a High/Low-Volt-
age Detect module (HLVD). This is a programmable cir-
cuit that sets both a device voltage trip point and the
direction of change from that point. If the device experi-
ences an excursion past the trip point in that direction, an
interrupt flag is set. If the interrupt is enabled, the pro-
gram execution branches to the interrupt vector address
and the software responds to the interrupt.

The High/Low-Voltage Detect Control register
(

) completely controls the operation of the

HLVD module. This allows the circuitry to be “turned
off” by the user under software control, which
minimizes the current consumption for the device.

The module’s block diagram is shown in 

.

R/W-0

R-0

R-0

R/W-0

R/W-0

R/W-1

R/W-0

R/W-1

VDIRMAG

BGVST

IRVST

HLVDEN

HLVDL<3:0>

bit 7

bit 0

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as ‘0’

-n = Value at POR

‘1’ = Bit is set

‘0’ = Bit is cleared

x = Bit is unknown

bit 7

VDIRMAG: Voltage Direction Magnitude Select bit

1

 = Event occurs when voltage equals or exceeds trip point (HLVDL<3:0>)

0

 = Event occurs when voltage equals or falls below trip point (HLVDL<3:0>)

bit 6

BGVST: Band Gap Reference Voltages Stable Status Flag bit

1

 = Internal band gap voltage references are stable

0

 = Internal band gap voltage reference is not stable

bit 5

IRVST: Internal Reference Voltage Stable Flag bit

1

 = Indicates that the voltage detect logic will generate the interrupt flag at the specified voltage range

0

 = Indicates that the voltage detect logic will not generate the interrupt flag at the specified voltage

range and the HLVD interrupt should not be enabled 

bit 4

HLVDEN: High/Low-Voltage Detect Power Enable bit

1

 = HLVD enabled

0

 = HLVD disabled

bit 3-0

HLVDL<3:0>: Voltage Detection Level bits

1111

 = External analog input is used (input comes from the HLVDIN pin) 

1110

 = Maximum setting 

.

.

.

0000

 = Minimum setting

See 

 for specifications.