PIC18F2420-I/ML Microchip Technology, PIC18F2420-I/ML Datasheet - Page 46

• Manufacturer Part Number: PIC18F2420-I/ML
• Description: IC PIC MCU FLASH 8KX16 28QFN
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2420-I/ML

• Program Memory Type: FLASH
• Program Memory Size: 16KB (8K x 16)
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 25
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: EUSART, I2C, MSSP, SPI
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 25
• Number Of Timers: 1 x 8
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DM163014, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit
• Package: 28QFN EP
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 40 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28QFN4 - SOCKET TRANS ICE 28QFN W/CABLEAC164322 - MODULE SOCKET MPLAB PM3 28/44QFN
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC18F2420/2520/4420/4520
4.4
PIC18F2420/2520/4420/4520 devices implement a
BOR circuit that provides the user with a number of
configuration and power-saving options. The BOR is
controlled
BOREN1:BOREN0 configuration bits. There are a total
of four BOR configurations which are summarized in
Table 4-1.
The BOR threshold is set by the BORV1:BORV0 bits. If
BOR is enabled (any values of BOREN1:BOREN0,
except ‘00’), any drop of V
D005) for greater than T
the device. A Reset may or may not occur if V
below V
Brown-out Reset until V
If the Power-up Timer is enabled, it will be invoked after
V
Reset
(parameter 33). If V
Power-up Timer is running, the chip will go back into a
Brown-out Reset and the Power-up Timer will be
initialized. Once V
Timer will execute the additional time delay.
BOR
independently configured. Enabling BOR Reset does
not automatically enable the PWRT.
4.4.1
When BOREN1:BOREN0 = 01, the BOR can be
enabled or disabled by the user in software. This is
done with the control bit, SBOREN (RCON<6>).
Setting SBOREN enables the BOR to function as
previously described. Clearing SBOREN disables the
BOR entirely. The SBOREN bit operates only in this
mode; otherwise it is read as ‘0’.
TABLE 4-1:
DS39631A-page 44
DD
BOREN1
BOR Configuration
rises above V
0
0
1
1
and
BOR
for
Brown-out Reset (BOR)
SOFTWARE ENABLED BOR
for less than T
an
the
by
BOREN0
BOR CONFIGURATIONS
DD
additional
Power-on
BOR
0
1
0
1
DD
rises above V
the
; it then will keep the chip in
DD
drops below V
BOR
BOR
rises above V
DD
(RCON<6>)
Unavailable
Unavailable
Unavailable
(parameter 35) will reset
BORV1:BORV0
SBOREN
below V
Available
Status of
. The chip will remain in
time
Timer
BOR
delay,
BOR
, the Power-up
BOR
(PWRT)
BOR
(parameter
BOR disabled; must be enabled by reprogramming the configuration bits.
BOR enabled in software; operation controlled by SBOREN.
BOR enabled in hardware in Run and Idle modes, disabled during
Sleep mode.
BOR enabled in hardware; must be disabled by reprogramming the
configuration bits.
.
while the
DD
T
PWRT
falls
and
Preliminary
are
Placing the BOR under software control gives the user
the additional flexibility of tailoring the application to its
environment without having to reprogram the device to
change BOR configuration. It also allows the user to
tailor device power consumption in software by elimi-
nating the incremental current that the BOR consumes.
While the BOR current is typically very small, it may
have some impact in low-power applications.
4.4.2
When BOR is enabled, 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.
4.4.3
When BOREN1:BOREN0 = 10, the BOR remains
under hardware control and operates as previously
described. Whenever the device enters Sleep mode,
however, the BOR is automatically disabled. When the
device returns to any other operating mode, BOR is
automatically re-enabled.
This mode allows for applications to recover from
brown-out situations, while actively executing code,
when the device requires BOR protection the most. At
the same time, it saves additional power in Sleep mode
by eliminating the small incremental BOR current.
Note:
BOR Operation
Even when BOR is under software control,
the BOR Reset voltage level is still set by
the BORV1:BORV0 configuration bits. It
cannot be changed in software.
DETECTING BOR
DISABLING BOR IN SLEEP MODE
 2004 Microchip Technology Inc.