PIC16F684-I/SLG Microchip, PIC16F684-I/SLG Datasheet - Page 98

• Manufacturer Part Number: PIC16F684-I/SLG
• Description: pic, flash, Microcontrollers, Microprocessors, Semiconductors and Actives, ic, mcu
• Manufacturer: Microchip

PIC16F684
12.3.4
The Power-up Timer provides a fixed 64 ms (nominal)
time-out on power-up only, from POR or Brown-out
Detect. The Power-up Timer operates from the 31 kHz
LFINTOSC oscillator. For more information, see
Section 3.4 “Internal Clock Modes”. The chip is kept
in Reset as long as PWRT is active. The PWRT delay
allows the V
uration bit, PWRTE, can disable (if set) or enable (if
cleared or programmed) the Power-up Timer. The
Power-up Timer should be enabled when Brown-out
Detect is enabled, although it is not required.
The Power-up Timer delay will vary from chip-to-chip
and vary due to:
• V
• Temperature variation
• Process variation
See
“Electrical Specifications”).
12.3.5
The BODEN0 and BODEN1 bits in the Configuration
Word register select one of four BOD modes. Two
modes have been added to allow software or hardware
control of the BOD enable. When BODEN<1:0> = 01,
the SBODEN bit (PCON<4>) enables/disables the
BOD allowing it to be controlled in software. By select-
ing BODEN<1:0>, the BOD is automatically disabled in
Sleep to conserve power and enabled on wake-up. In
this mode, the SBODEN bit is disabled. See
Register 12-1 for the configuration word definition.
FIGURE 12-3:
DS41202C-page 96
DD
DC
variation
Note 1: 64 ms delay only if PWRTE bit is programmed to ‘0’.
POWER-UP TIMER (PWRT)
BROWN-OUT DETECT (BOD)
DD
parameters
Internal
Internal
Internal
to rise to an acceptable level. A config-
Reset
Reset
Reset
V
V
V
DD
DD
DD
BROWN-OUT SITUATIONS
for
details
(Section 15.0
Preliminary
< 64 ms
64 ms
If V
(T
tions”), the Brown-out situation will reset the device.
This will occur regardless of V
not insured to occur if V
than parameter (T
On any Reset (Power-on, Brown-out Detect, Watchdog
timer, etc.), the chip will remain in Reset until V
above V
will now be invoked, if enabled and will keep the chip in
Reset an additional 64 ms.
If V
running, the chip will go back into a Brown-out Detect
and the Power-up Timer will be re-initialized. Once V
rises above V
64 ms Reset.
12.3.6
The PIC16F684 stores the BOD calibration values in
fuses located in the Calibration Word register (2008h).
The Calibration Word register is not erased when using
the specified bulk erase sequence in the “PIC12F6XX/
16F6XX
(DS41204) and thus, does not require reprogramming.
(1)
BOD
Note:
Note:
64 ms
64 ms
DD
DD
) (see Section 15.0 “Electrical Specifica-
drops below V
falls below V
(1)
BOD
(1)
The Power-up Timer is enabled by the
PWRTE bit in the Configuration Word
register.
BOD CALIBRATION
Memory
memory space. It belongs to the special
configuration
3FFFh), which can be accessed only during
programming. See “PIC12F6XX/16F6XX
Memory
(DS41204) for more information.
Address 2008h is beyond the user program
(see Figure 12-3). The Power-up Timer
BOD
BOD
, the Power-up Timer will execute a
BOD
BOD
).
Programming
Programming
 2004 Microchip Technology Inc.
DD
while the Power-up Timer is
for greater than parameter
memory
V
V
V
falls below V
BOD
BOD
BOD
DD
slew rate. A Reset is
space
Specification”
Specification”
BOD
(2000h-
DD
for less
rises
DD