AC162078 Microchip Technology, AC162078 Datasheet - Page 41

• Manufacturer Part Number: AC162078
• Description: HEADER INTRFC MPLAB ICD2 18F1330
• Manufacturer: Microchip Technology

Specifications of AC162078

• Accessory Type: Transition Header
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: ICD2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Not applicable / Not applicable

5.2
The MCLR pin provides a method for triggering an
external Reset of the device. A Reset is generated by
holding the pin low. These devices have a noise filter in
the MCLR Reset path which detects and ignores small
pulses.
The MCLR pin is not driven low by any internal Resets,
including the WDT.
In PIC18F1230/1330 devices, the MCLR input can be
disabled with the MCLRE Configuration bit. When
MCLR is disabled, the pin becomes a digital input. See
Section 10.1 “PORTA, TRISA and LATA Registers”
for more information.
5.3
A Power-on Reset pulse is generated on-chip
whenever V
allows the device to start in the initialized state when
V
To take advantage of the POR circuitry, tie the MCLR
pin through a resistor (1 k to 10 k) to V
eliminate external RC components usually needed to
create a Power-on Reset delay. A minimum rise rate for
V
time, see Figure 5-2.
When the device starts normal operation (i.e., exits the
Reset
(voltage, frequency, temperature, etc.) must be met to
ensure operation. If these conditions are not met, the
device must be held in Reset until the operating
conditions are met.
Power-on Reset events are captured by the POR bit
(RCON<1>). The state of the bit is set to ‘0’ whenever
a Power-on Reset occurs; it does not change for any
other Reset event. POR is not reset to ‘1’ by any hard-
ware event. To capture multiple events, the user
manually resets the bit to ‘1’ in software following any
Power-on Reset.
 2009 Microchip Technology Inc.
DD
DD
is adequate for operation.
is specified (parameter D004). For a slow rise
condition),
Master Clear (MCLR)
Power-on Reset (POR)
DD
rises above a certain threshold. This
device
operating
DD
parameters
. This will
FIGURE 5-2:
Note 1: External Power-on Reset circuit is required
V
2: R < 40 k is recommended to make sure that
3: R1  1 k will limit any current flowing into
DD
PIC18F1230/1330
D
only if the V
The diode D helps discharge the capacitor
quickly when V
the voltage drop across R does not violate
the device’s electrical specification.
MCLR from external capacitor C, in the event
of MCLR/V
Electrostatic Discharge (ESD) or Electrical
Overstress (EOS).
V
DD
R
C
EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW V
DD
PP
DD
R1
power-up slope is too slow.
pin breakdown, due to
powers down.
DD
PIC18FXXXX
MCLR
POWER-UP)
DS39758D-page 41