PIC18F2455-I/SP Microchip Technology Inc., PIC18F2455-I/SP Datasheet - Page 185

• Manufacturer Part Number: PIC18F2455-I/SP
• Description: Microcontroller; 24 KB Flash; 2048 RAM; 256 EEPROM; 24 I/O; 28-Pin-SPDIP
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F2455-I/SP

• A/d Inputs: 10-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 12 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 23
• Interface: I2C/SPI/USART/USB
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 24K Bytes
• Ram Size: 2K Bytes
• Speed: 48 MHz
• Timers: 1-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

17.0
PIC18F2450/4450 devices have a High/Low-Voltage
Detect module (HLVD). This is a programmable circuit
that allows the user to specify both a device voltage trip
point and the direction of change from that point. If the
device experiences an excursion past the trip point in
that direction, an interrupt flag is set. If the interrupt is
enabled, the program execution will branch to the
interrupt vector address and the software can then
respond to the interrupt.
REGISTER 17-1:
© 2006 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
bit 6
bit 5
bit 4
bit 3-0
Note 1:
VDIRMAG
R/W-0
HIGH/LOW-VOLTAGE DETECT
(HLVD)
See Table 21-4 in Section 21.0 “Electrical Characteristics” for specifications.
VDIRMAG: Voltage Direction Magnitude Select bit
1 = Event occurs when voltage equals or exceeds trip point (HLVDL3:HLDVL0)
0 = Event occurs when voltage equals or falls below trip point (HLVDL3:HLVDL0)
Unimplemented: Read as ‘0’
IRVST: Internal Reference Voltage Stable Flag bit
1 = Indicates that the voltage detect logic will generate the interrupt flag at the specified voltage
0 = Indicates that the voltage detect logic will not generate the interrupt flag at the specified voltage
HLVDEN: High/Low-Voltage Detect Power Enable bit
1 = HLVD enabled
0 = HLVD disabled
HLVDL3:HLVDL0: Voltage Detection Limit bits
1111 = Reserved
1110 = Maximum setting
.
.
.
0000 = Minimum setting
trip point
trip point and the LVD interrupt should not be enabled
U-0
—
HLVDCON: HIGH/LOW-VOLTAGE DETECT CONTROL REGISTER
W = Writable bit
‘1’ = Bit is set
IRVST
R-0
Advance Information
HLVDEN
R/W-0
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
HLVDL3
R/W-0
(1)
The
(Register 17-1) 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 block diagram for the HLVD module is shown in
Figure 17-1.
(1)
High/Low-Voltage
PIC18F2450/4450
HLVDL2
R/W-1
(1)
x = Bit is unknown
Detect
HLVDL1
R/W-0
DS39760A-page 183
(1)
Control
HLVDL0
R/W-1
register
bit 0
(1)