Hardware
Description 1/22/04 EWJ
Overview:
The PIC16F877/18F452 is a Microprocessor based system,
including input and output (I/O) interfaces, on a single integrated circuit. This
type of device is called a Microcontroller.
The '877/452 device contains several features
that are useful when using the device to control a process. Not all of the
features of the '877/452 are available at the same time so when the device is used
in an application such as the robot choices must be made as to what features
are going to be in the overall design.
The robot (I/O)
features:
Ports- The multi-function ports of the 16F877/18F452 processor are
available on the screw terminal expansion connectors. Some of these pins have
other functions not listed here. Please review the 16F877/18F452 data sheet and the
"C" programming manual for these other functions.:
The 8 bit port RB:
|
Bit |
Description |
Function |
Available on expansion connector JP7 |
|
RB0 |
I/O or External Interrupt |
Open |
Pin 1 |
|
RB1 |
I/O |
Open |
Pin 2 |
|
RB2 |
I/O |
Open |
Pin 3 |
|
RB3 |
Reserved to program '877 |
Open if using '452 |
Pin 4 |
|
RB4 |
I/O |
Open |
Pin 5 |
|
RB5 |
Reserved to program '452 |
Open if using '877 |
Pin 6 |
|
RB6 |
Reserved to program '877/452 |
NOT A USER FUNCTION |
Pin 7 |
|
RB7 |
Reserved to program '877/452 |
NOT A USER FUNCTION |
Pin 8 |
|
Ground |
|
|
Pin 9 |
The 8 bit port RC:
|
Bit |
Description |
Function |
Available on expansion connector JP8 |
|
RC0 |
I/O |
Open |
Pin 1 |
|
RC1 |
I/O |
Open or PWM out |
Pin 2 |
|
RC2 |
I/O |
Open or PWM out |
Pin 3 |
|
RC3 |
I/O |
Open |
Pin 4 |
|
RC4 |
I/O |
Open |
Pin 5 |
|
RC5 |
I/O |
Open |
Pin 6 |
|
RC6 |
I/O |
Open |
Pin 7 |
|
RC7 |
I/O |
Open |
Pin 8 |
|
Ground |
|
|
Pin 9 |
The 8 bit port RD:
|
Bit |
Description |
Function |
Available on expansion connector JP10 |
|
RD0 |
I/O LCD data |
Cannot be used when LCD in use |
Pin 1 |
|
RD1 |
I/O LCD data |
Cannot be used when LCD in use |
Pin 2 |
|
RD2 |
I/O LCD data |
Cannot be used when LCD in use |
Pin 3 |
|
RD3 |
I/O LCD data |
Cannot be used when LCD in use |
Pin 4 |
|
RD4 |
I/O LCD data |
Cannot be used when LCD in use |
Pin 5 |
|
RD5 |
I/O LCD data |
Cannot be used when LCD in use |
Pin 6 |
|
RD6 |
I/O LCD data |
Cannot be used when LCD in use |
Pin 7 |
|
RD7 |
I/O LCD data |
Cannot be used when LCD in use |
Pin 8 |
|
Ground |
|
|
Pin 9 |
Analog to Digital conversion- Eight inputs are provided to measure analog signals.
They are converted in the '877/452 to a 10bit digital value. Your software can
request this data.
|
Channel |
Description |
Available on expansion connector JP5 |
|
AN0/RA0 |
Analog in or Digital I/O |
Pin 1 |
|
AN1/RA1 |
Analog in or Digital I/O |
Pin 2 |
|
AN2/RA2 |
Analog in or Digital I/O |
Pin 3 |
|
AN3/RA3 |
Analog in or Digital I/O |
Pin 4 |
|
RA4 |
Digital I/O open drain |
Pin 5 |
|
AN4/RA5 |
Analog in or Digital I/O |
Pin 6 |
|
AN5/RE0 |
Cannot be used when LCD in use |
Pin 7 |
|
AN6/RE1 |
Cannot be used when LCD in use |
Pin 8 |
|
AN7/RE2 |
Cannot be used when LCD in use |
Pin 9 |
|
Ground |
|
Pin 10 |
Power Battery- Battery voltage is provided at JP1 DO NOT CONNECT BATTERY VOLTAGE TO INPUTS OF MICROCONTROLLER.
|
Signal |
Description |
Available on expansion connector JP1 |
|
Ground |
|
Pin 1 |
|
V battery |
12V Battery voltage |
Pin 2 |
|
Ground |
|
Pin 3 |
Regulated +5 Volts- This voltage is provided at JP3 and is used to power
your circuits.
DO NOT CONNECT +5V DIRECTLY TO
INPUTS OF MICROCONTROLLER.
(Connect a 20K resistor between the input
and +5V to create a logic 1 input.)
|
Signal |
Description |
Available on expansion connector JP3 |
|
Ground |
|
Pin 1 |
|
+5V |
Regulated +5V DC |
Pin 2 |
|
Ground |
|
Pin 3 |
Important links for understanding and
utilizing the Robot circuitry:
Microchip PIC16F877 datasheet
Microchip PIC18F452 datasheet
Microchip MPLAB-ICD development
system (16F877 Only)
Optional:
Schematics: