PIC18F45J10-I/ML Microchip Technology Inc., PIC18F45J10-I/ML Datasheet - Page 41

• Manufacturer Part Number: PIC18F45J10-I/ML
• Description: 44 PIN, 32 KB FLASH, 1024 RAM
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F45J10-I/ML

• A/d Inputs: 13-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 32
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin QFN
• Programmable Memory: 32K Bytes
• Ram Size: 1K Bytes
• Speed: 40 MHz
• Timers: 1-8 bit, 2-16 bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

4.2
The MCLR pin provides a method for triggering a hard
external Reset of the device. A Reset is generated by
holding the pin low. PIC18 extended microcontroller
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.
4.3
A Power-on Reset condition 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 kΩ to 10 kΩ) to V
eliminate external RC components usually needed to
create a Power-on Reset delay. A minimum rise rate for
V
time, see Figure 4-2.
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.
POR events are captured by the POR bit (RCON<1>).
The state of the bit is set to ‘0’ whenever a POR occurs;
it does not change for any other Reset event. POR is
not reset to ‘1’ by any hardware event. To capture
multiple events, the user manually resets the bit to ‘1’
in software following any POR.
4.4
Once a BOR has occurred, the Power-up Timer will
keep the chip in Reset for T
V
running, the chip will go back into a Brown-out Reset
and the Power-up Timer will be initialized. Once V
rises above V
additional time delay.
© 2006 Microchip Technology Inc.
DD
DD
DD
is adequate for operation.
drops below V
is specified (parameter D004). For a slow rise
condition),
Master Clear (MCLR)
Power-on Reset (POR)
Brown-out Reset (BOR)
(PIC18F2XJ10/4XJ10 Devices
Only)
DD
BOR
rises above a certain threshold. This
, the Power-up Timer will execute the
BOR
device
while the Power-up Timer is
PWRT
operating
(parameter 33). If
DD
parameters
. This will
Preliminary
DD
PIC18F45J10 FAMILY
FIGURE 4-2:
4.4.1
The BOR bit always resets to ‘0’ on any BOR or POR
event. This makes it difficult to determine if a BOR
event has occurred just by reading the state of BOR
alone. A more reliable method is to simultaneously
check the state of both POR and BOR. This assumes
that the POR bit is reset to ‘1’ in software immediately
after any POR event. If BOR is ‘0’ while POR is ‘1’, it
can be reliably assumed that a BOR event has
occurred.
In devices designated with an “LF” part number (such
as PIC18LF25J10), Brown-out Reset functionality is
disabled. In this case, the BOR bit cannot be used to
determine a BOR event. The BOR bit is still cleared by
a POR event.
Note 1: External Power-on Reset circuit is required
V
2: R < 40 kΩ is recommended to make sure that
3: R1 ≥ 1 kΩ will limit any current flowing into
DD
DETECTING BOR
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 pin breakdown, due to Electrostatic
Discharge (ESD) or Electrical Overstress
(EOS).
V
DD
R
C
EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW V
DD
DD
R1
power-up slope is too slow.
powers down.
DD
PIC18F45J10
MCLR
POWER-UP)
DS39682B-page 39