Microtronics PIC Lab-II User Manual

Microtronics Pakistan | www.electronicspk.com| PIC Lab II Manual [1]

Microtronics Pakistan

PIC Lab-II
Motherboard

User Manual

Microtronics Pakistan

Microtronics Pakistan | www.electronicspk.com| PIC Lab II Manual [2]

ongratulations on purchase of PIC Lab-II development board. The board supports most com­monly used 40 Pin Mid range PIC microcontroller units, and has on-board many commonly used
peripheral devices. All I/O lines are available through separate, well marked headers for daugh-

C

daughter board can be powered up from the motherboard.

Salient Features of Board.

ter boards, or projects. Every I/O line group is provided with a set of power supply, so that the

• Socket for 40 Pin PIC Microcontrollers (16F87x, 18FXXX)

• Changeable Crystal Oscillator (20MHz standard)

• 5 Push Switches

• 1 16x2 Character LCD

• USART (RS-232 Module)

• I2C EEPROM

• 1 PIZO Buzzer

• In Circuit Serial programming / Debugging Support

• 8 LED indicators

• 38KHz Modulated Infra Red Sensor

• Connector for two Analog Inputs

• Connector for Hardware driven PWM

• Connector for T0CKI

• Connector for I2C Bus

• All I/O lines available through Headers

• On Board regulated 5V 1A power supply.

Power Supply

The board uses 5V regulated power supply, in order to assure a constant supply of 5V, we recommend a
power source more than 5V. The recommendation is 9V at least 300mA load. If you are going to drive an
external load through the board, like motor, or LEDs etc, make sure that the supply current is appropriate.
In that case we recommend 9V-12V DC adapter, 800mA to 1000mA.

The adapter must have center pin supplying Positive. Reverse polarity is checked however. There is a
blocking diode, which will not allow the reverse polarity to reach the board. There is an On/OFF switch,
and a Power-ON LED indicator. The Voltage regulator IC, 7805, is rated as 1A, and gets heat up if heavy
load is put on it, or if a voltage adapter of more than 9V is used. The regulated is fitted with commercial
heat sink.

The Microcontroller

The board contains a socket for 40-Pin PIC microcontroller. Board comes with standard PIC 16F877A mi­crocontroller. However if you want to change, lets say to 18F452, simply take the IC out of socket and in­sert the one of your choice.

The Oscillator Circuit

The oscillator circuit consists of a crystal oscillator and two 22pF capacitors. The crystal oscillator is not
fixed soldered, rather there is a base, into which it can be inserted. The board comes with 20MHz crystal,
however if you want to change this to another frequency, just pull it out and insert the new one.

PIC 18F series are capable of multiplying the clock frequency by 4, to generate an internal high frequency
oscillator. They can run at a maximum of 40MHz, therefore using a 10MHz crystal, along with enabling an
internal PLL, will give a speed of 40MHz.

Microtronics Pakistan | www.electronicspk.com| PIC Lab II Manual [3]

In Circuit Serial Programming

Traditionally microcontrollers are programmed, using a device called programmer. The microcontroller is
taken out of the circuit, and put into the programmer to get it programmed. The processor is then inserted
back into the board to run the program. This is however quite cumbersome, to repeatedly take out the proc­essor. Microchip therefore introduced the idea of In Circuit Programming. This is also called ICSP. This
board supports In circuit Serial programming. However not all programmers have ICSP support. So you
will need a programmer with ICSP support, such as Microtronics PIC-PG2.

ICSP uses two of the microcontroller pins, RB6 and RB7, Called PGM and PGD respectively. If you are
going to use ICSP, these pins must not be tied to any circuit that should drain the signals from programmer
on these pins. The board, has kept this feature and RB6 and RB7 are not connected to any device. However
since these pins are available through headers, you can use them in your applications, then if the ICSP fails,
disconnect the device before programming.

The programmer also supplies 5V output, but this power is insufficient to supply the entire board. It is
therefore mandatory to keep the power on while programming . As soon as you connect the programmer
cable to the ICSP connector, the MCLR pin goes low, this inhibits the microcontroller to run any program.
Therefore, if your programmer does not have the mechanism to release MCLR pin, then after programming,
remove the cable, so that the program can run.

DIP Switch

There is an 8 switch DIP switch, labeled as Enable on board. This switch will connect or disconnect various
peripheral devices on board, so that the associated pins can be freed for use in other projects. We will talk
about the related Switch, in appropriate topics.

LED Indicators (PORTC.0 … PORTC.7)

PIC Lab-II has 8 Led indicators connected to PORTC of the microcontroller. The LEDs are connected
through 220 ohms current limiting resistor, and are sourced by the microcontroller. Therefore a logical 1, or
on state of the microcontroller pin will turn the corresponding LED ON.

DIP Switch 1, will enable or disable the LED module.
A number of other devices also use PORTC, therefore simultaneous use or connection of port pins to LEDs

may interfere with other device function. For example, USART uses RC5 and RC6 for communication, if
LEDs are enabled, this communication may Fail. Same is the case with Boot-Loader programming which
uses USART, therefore before programming using Boot-Loader, disable the LEDs using Dip-Switch 1.

Character LCD (PORTD.2,3,4,5,6,7)

The board contains a socket for HD44780 based character LCDs with back light. The LCD module can be
any, based upon HD44780 controller. Commonly used is 16x2 character LCD. The module uses 4 bit
mode, in which the highest 4 bits of PORTD are connected to data pins of LCD. PORTD.2 is connected to
Enable Pin, and PORTD.3 to RS-Pin of LCD. Thus following declarations must be used before initializing
the LCD (Proton Basic).

LCD_DTPIN PORTD.4
LCD_RSPIN PORTD.3
LCD_ENPIN PORTD.2

LCD can be enabled or disabled by using DIP-Switch-2

Infra-Red Remote Control Sensor (PORTA.3)

A large number of devices are now using infra-red remote controls to communicate. The standard protocol
is based upon 38KHz, modulated infra-red communication. The PIC Lab-II board contains a 38KHz, modu­lated Infra red sensor, that will detect the Infra-reds, which are modulated only at 38Khz. Most commonly
available remote controls for TV, CD and A/C use the same protocol. However they differ in codes they
transmit. The Infra-red Sensor is connected to, PORTA.3. this port is also analog input, therefore make
sure it is set to digital, and configured as Input to read the sensor.

Microtronics Pakistan | www.electronicspk.com| PIC Lab II Manual [4]

The infrared –Sensor can be enabled or disabled using DIP-Switch 3.

Push Switches

There are five push switches available on board. These switches have all 10K pull up resistors and will be
active low. Therefore when switch is not pressed the associated microcontroller pin will read a logical high
or 1. when switch is pressed, it connects the pin to ground thereby giving a Low state or logical 0.

The switches are named as SW3—SW7
The PORT Pins connected to these switches is as below:

Switch PORT Pin Comments

SW3 PORTE.0 DIP-Switch 4 to enable / disable
SW4 PORTE.1 DIP-Switch 5 to enable / disable
SW5 PORTB.0 PORTB.0 is also external interrupt, DIP SW-6
SW6 PORTE.2 Dip Switch 7 to enable / disable
SW7 PORTA.4 PORTA.4 is also external clock input for timer 0.

DOP Switch SW 8 to enable/disable

Reset Switch (MCLR)

Reset switch is located on the right hand corner and labeled as RST. When pressed the switch gives a logi­cal 0 to MCLR pin of microcontroller, which is reset, and starts the software from beginning. All RAM data
is cleared. EEPROM is preserved. Timers are cleared. The Reset switch is specially useful, for boot-loader
programming.

I2C EEPROM (PORTC.3, PORTC.4)

I2C communication bus is very commonly used in electronics devices. More and more devices are coming
up with I2C protocol support. The board contains an EEPROM Chip, (24c08) which is 8K EEPROM. This
chip is attached to microcontroller using PORTC.3 and PORTC.4. The 40 pin, PICs have these pins at­tached to internal hardware of I2C communication. PORTC.3 is SCL and PORTC.4 is SDA. Due to built in
I2C communication hardware, the software overhead is very much reduced.

The I2C bus contains 10K pull-ups on both SDA and SCL pins.
EEPROM is placed on an 8 pin base, it can be removed and another one inserted, if more memory is re-

quired. The EEPROMs have three address pins, which can be used to connect many more EEPROMs in
parallel. The board has however given this a permanent address of 000 . The I2C code for EEPROM is

1010. next three bits would be EEPROM chip address, and last bit is direction. Therefore the complete ad­dress to write on EEPROM would be: 1010 000 0 and to read it would be : 1010 000 1

I2C BUS (Connector)

The board also provides an I2C Bus as a connector, which contains connection for SDA and SCL pins
along with Power for daughter boards. The bus connects directly to PORTC.3 and PORTC.4 which are
hardware driven I2C pins. Keep it in mind that these pins have associated 10K pull up resistors already at­tached. In case these pins are being used for some other application this fact must be kept in mind.

USART (PORTC.6, PORTC.7)

The board contains a standard universal Serial Asynchronous receiver and transmitter. Many devices use
this protocol to communicate with other devices. The communication is hardware independent, and just
needs two wires, on for transmission and one for receiving data. PCs and some other devices, use a level
translator, to redefine the standard signals for logical 0 and 1. this is done so, to minimize noise interference
as well as prolong communication distance. To use these signals, they must be converted back to TTL level
logic. The PIC-Lab-II board contains Rs-232 level converter which converts these signals to TTL level, and
to transmission levels while sending data. Most PIC microcontrollers contain an internal hardware to man­age this communication, so that software development becomes easy. PORTC.6 and PORTC.7 are config-

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ured as hardware USART communication pins.

NOTE: since the PORTC is also connected to LEDs, if LEDs are enabled receiving data from USART is
interfered. It is therefore mandatory to disable, LEDs while using UASRT.

PIZO Buzzer (PORTA.5)

The board contains a connector for PIZO. The PIZO buzzer, module consists of a transistor and two resis­tors. The transistor connects directly to PORTA.5. The buzzer has to be given oscillatory signals, like a
train of 0s and 1s to make a sound.

I/O PORTS

All I/O lines, are available as headers on board for connection to other devices or daughter boards. The
headers are separated fro each PORT, and the number of header pins are according to the I/O lines available
on the respective port. Each port header is provided with power supply for the daughter board.

T0CKI Connector (PORTA.4)

Although this pin is available trough standard PORTA header, it has been provided separately along with
power supply, to used as external clock signals for Timer 0. The pin is also general purpose and can be used
as a serial communication between two boards directly connected together. Remember PORTA.4 is open
collector and it will need an external PULL up resistor. Fortunately SW7 is also connected to this port pin,
and has a pull-up resistor, so enabling SW7 will provide the necessary Pull-Up resistor, in that case don’t
press the button, data will be received through TOCKI connector.

Analog input Connectors (PORTA.0, PORTA.1)

Many PIC microcontrollers, give analog to digital conversion on chip. This is quite advantageous, as many
sensors give analog data. Although the number of analog inputs on a chip vary, yet if we talk about
16F877A, it has analog inputs on PORTA and E. all these pins are available for projects through PORT
headers. However we have specially included two connectors, from PORTA.0 and PORTA.1 along with
power supply, on board. These three pin connectors can be used directly to any analog device, giving upto
5V analog signal.

Pulse Width Modulation Connector (PORTC.2)

Pulse Width modulation is a common technique used to alter the speed of motors etc. although PWM can
be achieved on any digital pin, PIC microcontrollers have inbuilt hardware, that once set keeps on sending
PWM waveform to the device, despite processor busy in other jobs. This is really a multi tasking. 16F877
has two hardware PWM modules, one of them is on PORTC.2 which is available through port header, as
well as through this PWM connector, which also has power supply for daughter board if required.

Boot Loader

The supplied 16F877A microcontroller comes with a pre-programmed Boot loader software. This software
eliminates the need for an external programmer device. The boot loader program has an associated part
which will run on windows terminal. The boot-loader is configured to work with 20MHz crystal, and at top
BAUD speed of 115K asynchronous serial communication. Therefore configure your windows terminal to
use 115K speed.

Load the program hex file, which you want to load. Connect serial cable to PIC Lab-II board. Turn power
ON, press reset button, and immediately click on Write button on boot loader windows application. This
will immediately write the software into your microcontroller.

External programmer:

In case you want to use an external programmer, select one which has support for ICSP, this will facilitate
the programming job, and you will not have to remove the microcontroller from its socket again and again.
The board supports even low voltage programming, PGM pin is connected to PORTB.3 When High the

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microcontroller will be programmed by LVP. This is usually all set by the programmer itself. All you need
to know is that the programmer might use RB3, RB6 and RB7 so, your application must not be using them
at-least at the time of programming, the pins should be free. By default these pins are free on board. If you
are connecting an external board, just remove the connector.

Keep the system power on while programming, as the programmers can give only small amount of power,
which is enough for microcontroller, but not for the entire board.

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Title

Number Revi sionSize

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Date: 14-Mar-2008 Sheet of
File: D:\PIC3\40Pin.Ddb Drawn By:

1
2

B1

9V

D1

4004

+

C1

100u

Vin

1

GND

2

Vout

3

U1
7805

+

C2
100u

R1
330

LED1

Pwr

SW1

ON-OFF

VDD

RA0

2

RA1

3

RA2

4

RA3

5

RA4/T0CKI

6

RA5/SS

7

RB0/INT

33

RB1

34

RB2

35

RB3

36

RB4

37

RB5

38

RB6

39

RB7

40

RC0/T0OSO/T1CKI

15

RC1/T0OSI

16

RC2/CCP1

17

RC3/SCK/SCL

18

RC4/SDI/SDA

23

RC5/SDO

24

RC6

25

RC7

26

RD0/PSP0

19

RD1/PSP1

20

RD2/PSP2

21

RD3/PSP3

22

RD4/PSP4

27

RD5/PSP5

28

RD6/PSP6

29

RD7/PSP7

30

RE0/RD

8

RE1/WR

9

RE2/CS

10

MCLR/VPP

1

OSC1/CLKIN13OSC2/CLKOUT

14

U2

16F877A

Y1

20MHz

C3
22p

C4
22p

R2
10K

VDD

SW2

RST

MCLR

RA0
RA1
RA2
RA3
RA4
RA5
RB0
RB1
RB2
RB3
RB4
RB5
RB6
RB7
RE0
RE1 RE2

RC0
RC1
RC2
RC3
RC4
RC5
RC6
RC7
RD0
RD1
RD2
RD3
RD4
RD5
RD6
RD7

LED2LED3LED4LED5LED6LED7LED8LED9

1234567

8

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9

RP1
220

RC0

RC1

RC2

RC3

RC4

RC5

RC6

RC7

1
6
2
7
3
8
4
9
5

J8

DB9

R1 IN

13

R2 IN

8

T1 IN

11

T2 IN

10

GND

15

V+

2

V-

6

VCC

16

R1 OUT

12

R2 OUT

9

T1 OUT

14

T2 OUT

7

C1+

1

C1 -

3

C2+

4

C2 -

5

U3MAX232

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C5

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+

C6
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C7
10u

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10u

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VDD

T2OUT

T2OUT R2IN
R2IN

RC7

RC6

R1IN T1OUT

T1OUT

1
2
3
4
5
6
7
8
9
10

J2
PORTB

1
2
3
4
5
6
7
8
9
10

J3
PORTC

1
2
3
4
5
6
7
8
9
10

J4
PORTD

RB0
RB1
RB2
RB3
RB4
RB5
RB6
RB7

RC0
RC1
RC2
RC3
RC4
RC5
RC6
RC7

RD0
RD1
RD2
RD3
RD4
RD5
RD6
RD7

VDD

VDD

VDD

1
2
3
4
5
6
7
8

J5

PORTA

1
2
3
4
5

J6

PORTE

RA0
RA1
RA2
RA3
RA4
RA5

VDD

RE0
RE1
RE2

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SW3 SW4 SW5 SW6 SW7

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DIP1
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SW3

SW4

SW5

SW6

SW7

RB0

RE0

RE1

RE2

RA4

1 16

R4A
10K

2 15

R4B
10K

3 14

R4C
10K

4 13

R4D
10K

5 12

R4E
10K

IRERA3

VDD

1
2
3

IR1

IR

VDD

C9

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VDD

IRE

6 11

R4F
10K

Q6

C828

R6

2.2K

R5

2.2K

1

2

PIZO1
PIZO

VDD

RA5

1
2
3
4
5
6

J9

ICSP

MCLR
VDD
VSS
RB7
RB6
RB3

A0

1

A1

2

A2

3

G4SDA

5

SCL

6

WP

7

VCC

8

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RC4

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R4G
10K

8 9

R4H
10K

LED

LED

GND1VCC2VEE3RS4RW5E6D07D18D29D310D411D512D613D714LED +15LED -

16

Charcter LCD

LCD1 LCD

RD2

RD3

RD4

RD5

RD6

RD7

R8

1.5K

LCD

1
2
3

J10

TOCKI

VDD

R9
10K

VDD

RA4

LCD

VDD

1
2
3
4

J11

I2CBUS

RC3
RC4

VDD

1
2
3

J12
PWM

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RC2

1
2
3

J13

AN0

1
2
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J14

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