Datasheet

© 2007 Microchip Technology Inc. DS39599G-page 233
PIC18F2220/2320/4220/4320
22.1 Control Register
The Low-Voltage Detect Control register controls the
operation of the Low-Voltage Detect circuitry.
REGISTER 22-1: LVDCON: LOW-VOLTAGE DETECT CONTROL REGISTER
U-0 U-0 R-0 R/W-0 R/W-0 R/W-1 R/W-0 R/W-1
— — IRVST LVDEN LVDL3
(1)
LVDL2
(1)
LVDL1
(1)
LVDL0
(1)
bit 7 bit 0
Legend:
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 7-6 Unimplemented: Read as ‘0’
bit 5 IRVST: Internal Reference Voltage Stable Flag bit
1 = Indicates that the Low-Voltage Detect logic will generate the interrupt flag at the specified voltage
range
0 = Indicates that the Low-Voltage Detect logic will not generate the interrupt flag at the specified
voltage range and the LVD interrupt should not be enabled
bit 4 LVDEN: Low-Voltage Detect Power Enable bit
1 = Enables LVD, powers up LVD circuit
0 = Disables LVD, powers down LVD circuit
bit 3-0 LVDL3:LVDL0: Low-Voltage Detection Limit bits
(1)
1111 = External analog input is used (input comes from the LVDIN pin)
1110 = 4.50V-4.78V
1101 = 4.20V-4.46V
1100 = 4.00V-4.26V
1011 = 3.80V-4.04V
1010 = 3.60V-3.84V
1001 = 3.50V-3.72V
1000 = 3.30V-3.52V
0111 = 3.00V-3.20V
0110 = 2.80V-2.98V
0101 = 2.70V-2.86V
0100 = 2.50V-2.66V
0011 = 2.40V-2.55V
0010 = 2.20V-2.34V
0001 = 2.00V-2.12V
0000 = Reserved
Note 1: LVDL3:LVDL0 modes which result in a trip point below the valid operating voltage of the device are not tested.