PIC16F877A-I/PT Microchip Technology Inc., PIC16F877A-I/PT Datasheet - Page 136

• Manufacturer Part Number: PIC16F877A-I/PT
• Description: 44 PIN, 7 KB FLASH, 368 RAM, 33 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F877A-I/PT

• A/d Inputs: 8-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 33
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin TQFP
• Programmable Memory: 14K 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

PIC16F87X
12.17
PIC16F87X microcontrollers can be serially pro-
grammed while in the end application circuit. This is
simply done with two lines for clock and data and three
other lines for power, ground, and the programming
voltage. This allows customers to manufacture boards
with unprogrammed devices, and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware, or a custom firm-
ware to be programmed.
When using ICSP, the part must be supplied at 4.5V to
5.5V, if a bulk erase will be executed. This includes
reprogramming of the code protect, both from an on-
state to off-state. For all other cases of ICSP, the part
may be programmed at the normal operating voltages.
This means calibration values, unique user IDs, or user
code can be reprogrammed or added.
For complete details of serial programming, please
refer to the EEPROM Memory Programming Specifica-
tion for the PIC16F87X (DS39025).
12.18 Low Voltage ICSP Programming
The LVP bit of the configuration word enables low volt-
age ICSP programming. This mode allows the micro-
controller to be programmed via ICSP using a V
source in the operating voltage range. This only means
that V
instead be left at the normal operating voltage. In this
mode, the RB3/PGM pin is dedicated to the program-
ming function and ceases to be a general purpose I/O
pin. During programming, V
pin. To enter Programming mode, V
to the RB3/PGM, provided the LVP bit is set. The LVP
bit defaults to on (‘1’) from the factory.
DS30292C-page 134
PP
does not have to be brought to V
In-Circuit Serial Programming
DD
is applied to the MCLR
DD
must be applied
IHH
, but can
DD
If Low Voltage Programming mode is not used, the LVP
bit can be programmed to a '0' and RB3/PGM becomes
a digital I/O pin. However, the LVP bit may only be pro-
grammed when programming is entered with V
MCLR. The LVP bit can only be charged when using
high voltage on MCLR.
It should be noted, that once the LVP bit is programmed
to 0, only the High Voltage Programming mode is avail-
able and only High Voltage Programming mode can be
used to program the device.
When using low voltage ICSP, the part must be supplied
at 4.5V to 5.5V, if a bulk erase will be executed. This
includes reprogramming of the code protect bits from an
on-state to off-state. For all other cases of low voltage
ICSP, the part may be programmed at the normal oper-
ating voltage. This means calibration values, unique
user IDs, or user code can be reprogrammed or added.
Note 1: The High Voltage Programming mode is
2: While in Low Voltage ICSP mode, the
3: When using low voltage ICSP program-
4: RB3 should not be allowed to float if LVP
5: LVP mode is enabled by default on all
6: Disabling LVP will provide maximum com-
always available, regardless of the state
of the LVP bit, by applying V
MCLR pin.
RB3 pin can no longer be used as a gen-
eral purpose I/O pin.
ming (LVP) and the pull-ups on PORTB
are enabled, bit 3 in the TRISB register
must be cleared to disable the pull-up on
RB3 and ensure the proper operation of
the device.
is enabled. An external pull-down device
should be used to default the device to
normal operating mode. If RB3 floats
high, the PIC16F87X device will enter
Programming mode.
devices shipped from Microchip. It can be
disabled by clearing the LVP bit in the
CONFIG register.
patibility to other PIC16CXXX devices.
2001 Microchip Technology Inc.
IHH
to the
IHH
on