PIC16F88-I/SO Microchip Technology Inc., PIC16F88-I/SO Datasheet - Page 135

• Manufacturer Part Number: PIC16F88-I/SO
• Description: 18 PIN, 7 KB FLASH, 368 RAM, 16 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F88-I/SO

• A/d Inputs: 7-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 16
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 18-pin SOIC
• Programmable Memory: 7K Bytes
• Ram Size: 368 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

15.3
PIC16F87/88 devices have a noise filter in the MCLR
Reset path. The filter will detect and ignore small
pulses.
It should be noted that a WDT Reset does not drive
MCLR pin low.
The behavior of the ESD protection on the MCLR pin
has been altered from previous devices of this family.
Voltages applied to the pin that exceed its specification
can result in both MCLR and excessive current beyond
the device specification during the ESD event. The
circuit, as shown in Figure 15-2, is suggested.
The RA5/MCLR/V
(default), or as an I/O pin (RA5). This is configured
through the MCLRE bit in Configuration Word 1.
FIGURE 15-2:
15.4
A Power-on Reset pulse is generated on-chip when
V
advantage of the POR, tie the MCLR pin to V
described in Section 15.3 “MCLR”. A maximum rise
time for V
Characteristics” for details.
 2005 Microchip Technology Inc.
DD
Note:
Note 1: External Power-on Reset circuit is required
rise is detected (in the range of 1.2V-1.7V). To take
MCLR
2: R < 40 k is recommended to make sure that
3: R1 = 1 k to 10 k will limit any current flow-
Power-on Reset (POR)
DD
For this reason, Microchip recommends
that the MCLR pin no longer be tied
directly to V
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.
ing into MCLR from external capacitor C
(0.1 F), in the event of RA5/MCLR/V
breakdown due to Electrostatic Discharge
(ESD) or Electrical Overstress (EOS).
D
is specified. See Section 18.0 “Electrical
V
DD
PP
R
C
pin can be configured for MCLR
EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW V
DD
DD
DD
.
power-up slope is too slow.
R1
powers down.
DD
PIC16F87/88
MCLR
POWER-UP)
PP
DD
pin
, as
When the device starts normal operation (exits the
Reset condition), device operating parameters (volt-
age, frequency, temperature,...) 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. For more information, see Application Note,
AN607 “Power-up Trouble Shooting” (DS00607).
15.5
The Power-up Timer (PWRT) of the PIC16F87/88 is a
counter that uses the INTRC oscillator as the clock
input. This yields a count of 72 ms. While the PWRT is
counting, the device is held in Reset.
The power-up time delay depends on the INTRC and
will vary from chip-to-chip due to temperature and
process variation. See DC parameter #33 for details.
The PWRT is enabled by clearing configuration bit
PWRTEN.
15.6
The Oscillator Start-up Timer (OST) provides a 1024
oscillator cycle (from OSC1 input) delay after the
PWRT delay is over (if enabled). This helps to ensure
that the crystal oscillator or resonator has started and
stabilized.
The OST time-out is invoked only for XT, LP and HS
modes and only on Power-on Reset or wake-up from
Sleep.
15.7
The configuration bit, BOREN, can enable or disable
the Brown-out Reset circuit. If V
(parameter D005, about 4V) for longer than T
(parameter #35, about 100 s), the brown-out situation
will reset the device. If V
than T
Once the brown-out occurs, the device will remain in
Brown-out Reset until V
Power-up Timer (if enabled) will keep the device in
Reset for T
should fall below V
Reset process will restart when V
with the Power-up Timer Reset. Unlike previous PIC16
devices, the PWRT is no longer automatically enabled
when the Brown-out Reset circuit is enabled. The
PWRTEN
independent of each other.
BOR
Power-up Timer (PWRT)
Oscillator Start-up Timer (OST)
Brown-out Reset (BOR)
, a Reset may not occur.
PWRT
and
(parameter #33, about 72 ms). If V
BOREN
BOR
PIC16F87/88
during T
DD
DD
falls below V
configuration
rises above V
PWRT
DD
DD
DS30487C-page 133
rises above V
falls below V
, the Brown-out
BOR
BOR
bits
for less
. The
BOR
BOR
BOR
are
DD