Switch matrix Controller

A Project Report on

“SWITCH MATRIX CONTROLLER”

Carried out at

ELECTRONICS AND RADAR DEVELOPMENT ESTABLISHMENT (LRDE),

DEFENCE R&D ORGANIZATION, BANGALORE

Submitted in partial fulfillment of the requirement of degree of B.Tech in Electronics and Communication Engineering

AT

TEZPUR UNIVERSITY, ASSAM

NAPAM, TEZPUR-784028

Submitted by

Paban Sarma (ELB10011)

Sushanta Bordoloi (ELB10025)

Pranamita sarma (ELB10064)

CERTIFICATE

This is to certify that the project report entitled ”Switch Matrix Controller”

submitted by Paban Sarma, Sushanta Bordoloi and Pranamita Sarma; students of

“Tezpur University” , in partial fulfillment of the requirement of summer

training/project for award of B.Tech degree in “Electronics and Communication

Engineering” at “Tezpur University” have successfully completed the project at

Radar ‘A’ Division, LRDE, Bangalore during the period of June-July, 2012.

Mrs Paramita Barua Mrs. D Anuradha Scientist ‘D’ Scientist ‘F’ Radar ‘A’ Radar ‘A’ Signal Processing Lab Signal Processing Lab LRDE, Bangalore LRDE, Bangalore Date: Date:

ACKNOWLEDGEMENT

A project work can’t be worked out individually; it is a result of teamwork and guidence. The

satisfaction of the successful completion of the work will be incomplete without mentioning the

people under whose guidance the output appears.

We are grateful to Mrs. D. Anuradha (Sc. F, ARD, LRDE) for her kind permission to do a project

work at the ‘A’ RADAR DIVISION. We would like to express our gratitude to the administration

of the organization that provides us an opportunity to be part of it and gather a lifetime

experience.

We would like to express our sincere thanks and gratitude to Mrs. Paramita Barua and Mr.

Jerin K. James (STA B, ARD, LRDE) who helped us a lot with valuable instructions throughout

the course of the project , that leads the final result.

We would like to thank Dr. J. C. Dutta (HoD, dept. of ECE, TU) and the T&P Cell of Tezpur

University for the kind permission to do an outside project work.

ABSTRACT

In a Radar System for proper imaging there are number of antennas, which acts as transmitter

and receiver or as transciever accordingly. Among the available options the proper transmitter

and receiver is selected by giving proper control signals to the switch matrix that is controlling

the antenna system. The project aims to develop a control system that will generate the control

signal for the switch matrix so that the proper antenna gets activated as receiver/transmitter.

The switch matrix controller is a microcontroller (8051) based control circuit. The

microcontroller is programmed to serially receive control byte from PC. Then it will manipulate

the control byte and accordingly generate control signals for the switch matrix.

This project includes, study of 8051microcontroller (architecture, programming and

interfacing); study of serial communication (RS232 protocol); interfacing between logic levels

with max232; study of switch matrix (RF switches such as SPDT, SP4T).

The report provides a detailed description on the design procedure.

Table of contents

SL no. Title Page no.

1 Introduction……………………………………………………………. 1

2 The 8051 microcontroller………………………………………… 6

3 Serial Communication……………………………………………… 26

4 RF Switch………………………………………………………………… 31

5 Design of the control circuit…………………………………… 35

6 Programming the microcontroller………………………… 38

7 Conclusion…………………………………………………………….. 44

Appendix A 45

Appendix B 46

Appendix C 47

Appendix D 49

Bibliography 51

Switch Matrix Controller LRDE, DRDO

Tezpur University 1 June-July,2012

1. Introduction

1.1 Radar System

1.1.1 Introduction and basic principle

The term RADAR is an abbreviation for RAdio Detection And Ranging. Radar is an

electromagnetic system for the detection and location of reflecting objects such as

aircraft, ships, spacecrafts, vehicles and the natural environment. It operates by

radiating energy into space and detecting the echo signal reflected from an object or

target. The reflected energy that is returned indicates presence of object; moreover by

comparing received echo signal with transmitted one location and other target related

information can be obtained. The basic principle of radar is illustrated below in fig 1.1.

Fig 1.1 Radar principle

1.1.2 Basic Components

A radar system consists of the following basic components, viz

Transmitter: It creates the radio wave of desired properties to be sent towards

the target. It must amplify the generated wave up to the sufficient power level so

that it can travel without attenuation and we can get our work done.

Receiver: the receiver is there to receive the signal getting reflected from the

target. Since output of radar depends on received echo signal only, the receiver

plays a great role in overall performance of the system



Antenna: Radar systems contain one or more antennas for transmitting the radio

wave and receive the reflected.

Switch matrix: this matrix alternately connects the antennas to the transmitter

and receiver.

Synchronizer: This unit is important for coordination of timings for range

determination.

Processing unit: this unit processes the received signal according to sent signals

and target informations are evaluated.

Display: This unit indicates the target informations achieved by the system. This

unit may be of different type depending on the radar system concerned.

Power supply: This unit supplies power to the different blocks of the system.

A block diagram is provided in figure 1.2 for better visualization.

Fig 1.2 Basic components of a RADAR system



1.1.3 Applications

Since its evolution radar has been used to detect targets on ground, underwater, in air

space. The major areas of radar application are listed below.

i) Military

ii) Remote Sensing

iii) Air traffic Control

iv) Aircraft Safety and Navigation

v) Ship Safety

vi) Space etc.

1.2 Antennas in Radar

As mentioned in the basic building blocks of Radar, Antennas plays great role in the

system. The radio wave generated by the transmitter is spread towards target areas by

means of an antenna. A Radar system therefore contains at least one antenna; however in

practice there exists multiple numbers of antennas in a system. The multiple numbers of

antennas are to spread the wave in required directions, at required time interval so that

accurate information about target can be retrieved.

The reception of reflected signal is also being done by the antennas. A system may contain

single or multiple numbers of receiver antennas.

An antenna in a radar system may be a dedicated receiver, dedicated transmitter or a bi-

directional one i.e. a transceiver. According to the function switching should be done.

1.3 Switch matrix for Radar

As we see, though there may exist multiple numbers of antennas in a radar system, only

one antenna can work as transmitter/receiver at a time. The activated antenna should be

now connected to the proper channel. The way of disconnecting one antenna and

connecting another one is an impractical way of doing the task as it is time consuming and

cannot be achieved in real field. To overcome this problem a switch matrix is used in

between the antennas and the transmitter/ receiver devices. The switch matrix is basically

comprise of RF switches (such as SP2T, SP4T) that provides a way to establish connection

between different pair of RF sources (antenna, transmitter, receiver) according to the



control signal fed to it. Thus switch matrix is a multiplexure kind of arrangement that

depending on control signal connects one of the multiple options available. Fig 1.3 below

explains the function of switch matrix in a system.

Fig 1.3 Block diagram of antenna array to channel connection via switch matrix

1.4 Switch matrix controller

Use of the switch matrix simplifies the way of establishing connection between antenna

and corresponding channels (Txr/Rxr). But the way of providing the control signal to the

matrix is a problem here. Manual way of feeding the signal is feasible for the purpose of

experiment but it will be time consuming and cannot be achieved in real time application.

Therefore we need a switch matrix controller circuit for the radar system that will

automatically generate the control signal for the switch matrix depending on the

requirements.

The project aims to develop a microcontroller based switch matrix controller circuit that

will receive the necessary information (control word) from a PC, decode the information

and will automatically generate the control signals.

1.5 The Microcontroller based control circuit

Fig 1.4 below shows a block representation of the project to be designed.



Fig 1.4 Block diagram of the switch matrix controller

1.6 Components used

1.6.1 Hardware

1. Microcontroller 8051(AT89C51)

2. Max232 chip

3. 7408 logic IC’s

4. LED’s

5. DB9 connectors

1.6.2 Software tools

1. Orcad capture (To design schematic and PCB layout)

2. Keil uVision (for programming microcontroller)

1.7 Conclusion

Throughout the project we came across different technical terms, equipments & tools

such as microcontroller, serial communication, RF switch, Orcad, Keil, etc. The later

part of the report gives a detailed description of the phases towards completion of the

project work.



2. The 8051 Microcontroller

2.1 What is a Microcontroller?

Microcontrollers are the preferred choice for many embedded systems. An embedded

system uses a microcontroller to do one task only. A printer is an example of an embedded

system since it performs only one task, namely, getting data and printing it.

There are differences between a microprocessor and a microcontroller. The

microprocessors contain no RAM, ROM and I/O ports on the chip itself. They are

commonly referred to as general purpose microcontrollers. A system designer using a

general purpose

Microprocessors such as Intel’s x86 family or Motorola’s 680x0 must add RAM, ROM, I/O

ports and timers externally to make them functional. In contrast the microcontrollers have

a CPU on addition to fixed amount of RAM, RAM, I/O ports and timer embedded together

on the chip itself. Some microcontroller manufacturers have gone as far as integrating an

ADC (analog to digital converter) and other peripherals to the microcontroller.

Fig 2.1 Microprocessor system contrasted with microcontroller system

In an embedded system there is only one application system that is typically burned into

ROM. An x86 PC contains or is connected to various embedded products such as the

keyboard, printer, modem, mouse, CD-ROM driver and so on. Table 2.1 shows some

applications of micro controllers as embedded products in our daily life.



Table 2.1: Some embedded products using microcontrollers

2.2 Overview of 8051 Microcontroller

In 1981, Intel Corporation introduced an 8-bit microcontroller called the 8051. This

microcontroller had 128 bytes of RAM, 4k bytes of on chip ROM, two timers, one serial

port and four I/O ports all on a single chip. At that time it was also referred to as “system

on a chip”. The 8051 is an 8-bit processor, meaning the CPU can work on only 8 bits of data

at a time. Data larger than 8 bits has to be broken into 8 bit pieces to be processed by the

CPU. Table 2.2 shows the main features of the 8051 microcontroller.

Feature Quantity

ROM 4k bytes

RAM 128 bytes

Timer 2

I/O pins 32

Serial ports 1

Interrupt sources 6

Table 2.2: Features of the 8051 microcontroller

There are two other members in the 8051 family of microcontrollers. They are the 8052

and 8031. The 8052 has 256 bytes of RAM and 3 timers. It also has 8K bytes of on chip

Home Office Auto

Appliances, Intercom,

Telephones, Security

systems, Fax machines,

TVs, Camcorder, Remote

control, Video games,

Cellular phones, Musical

instruments, Camera,

Toys, Paging, Microwave

etc.

Telephones, Computers,

Fax machine, Copier,

laser printer, color

printer, paging security

systems etc.

Trip computers, Engine

control, Air bags, ABS,

Instrumentation,

Transmission control,

Climate control, Keyless

entry etc.



program ROM instead of 4K bytes. The 8031 chip is often referred to as a ROM-less 8051

since it has 0K bytes of on chip ROM. To use this chip one must add external ROM to it.

The external ROM must contain the program that the 8031 will fetch and execute. The

ROM containing the program attached to the 8031 can be as large as 64 bytes. We can

also add external I/O to the 8031.

The 8051 is available in different memory types, such as UV-EEPROM, flash, NV-RAM etc,

all of which has different part numbers. The UV-EPROM version of the 8051 is the 8751.

The flash ROM version is marketed by many companies including Atmel corp. and Dallas

Semiconductor. The Atmel flash 8051 is called AT89C51. This is a popular and inexpensive

chip used in many small projects. The Dallas Semiconductor’s flash 8051 microcontroller is

the DS89C4x0. The NV-RAM version of the 8051 made by Dallas semiconductor is called

DS5000. In this project we are using the Atmel Corporation’s AT89C51 microcontroller.

2.3 Architecture and Organization

2.3.1 What’s inside the 8051 microcontroller?

Fig 2.2 shows the block diagram of 8051 microcontroller.

Fig 2.2 inside the 8051 microcontroller

2.3.2 The registers



In the CPU, the registers are used to store information temporarily. The information could

be a byte of the data to be processed, or an address pointing to the data to be fetched.

The 8051 registers are generally 8-bit registers. With an 8-bit data type, any data larger

than 8 bits must be broken into 8 bit chunks before it is processed. The most widely used

registers of the 8051 are A (accumulator), B. R0, R1, R2, R3, R4, R5, R6, R7, DPTR (data

pointer) and PC (program counter). All the above registers are 8-bits, except DPTR and the

program counter. The accumulator is used for all arithmetic and logic instructions.

2.3.3 RAM memory space allocation in 8051

There are 128 bytes of RAM in the 8051. The 128 bytes of RAM inside the 8051 are

assigned address 00 to 77H. These 128 bytes are divided into three different groups as

follows:

1. A total of 32 bytes from locations 00 to 1FH are set aside for register bank and stack.

2. A total of 32 bytes from locations 20H to 2FH are set aside for bit addressable

read/write memory.

3. A total of 80 bytes from locations 30H to 7FH are used for read and write storage

(scratch pad). These 80 locations of RAM are widely used for the purpose of storing data

and parameters by 8051 programmers.

2.3.4 Register banks in 8051

A total of 32 bytes of RAM are set aside for the register banks and stacks. These 32 bytes

are divided into 4 banks of registers in which each bank has 8 registers, R0-R7. RAM

location 0 to 07 is allocated to bank 0. The second bank starts at ROM location 08, and so

on. Fig 2.3 shows how the 32 bytes are allocated into 4 banks.

Fig 2.3 RAM allocation in 8051



When the 8051 is powered up, the register bank 0 acts as default register bank. i.e, when

8051 is powered up; the RAM locations 0-7 are accessed. However, we can switch to

other banks by the PSW (program status word) register.

2.3.5 Stacks in 8051

The stack is a section of RAM used by the CPU to store information temporarily. This

information could be data or an address. The CPU needs this storage area since there are

only a limited number of registers. The register used to access the stack is called the SP

(stack pointer) register. The stack pointer in the 8051 is only 8-bit wide, which means it

can take values of 00 to FFH. When the 8051 is powered up, the SP register contains the

value 07. This means that RAM location 08 is the first location used for the stack by the

8051.

As we see from the fig 2.3, the RAM location 08 also belongs to the register R0 of register

bank 1. In other words, the register bank 1 and the stack are using the same memory

space. If in a program we need to use register bank 1, we must allocate another area of

RAM for the stack.

2.4 Pin Configuration

Fig 2.4 shows the pin configuration of the 8051 microcontroller.

Fig 2.4 8051 pin configuration



2.5 Pin Description

The 8051 is a 40 pin IC chip. Of the 40 pins, a total of 32 pins are set aside for the four

ports P0, P1, P2 and P3, where each port ta es 8 pins. The rest of the pins are designated

as cc, D, TAL1, TAL , RST, E A , S E and ALE.

2.5.1 Vcc

Pin 40 provides supply voltage to the chip. The voltage source is +5v.

2.5.2 GND

Pin 20 in the 8051 is ground.

2.5.3 XTAL1 and XTAL2

The 8051 has an on chip oscillator but requires an external clock to run it. A quartz crystal

oscillator is connected to inputs XTAL1 (pin 19) and XTAL2 (pin 18). The crystal oscillator

needs two capacitors. One side of each capacitor is connected to ground. Fig 2.5 shows the

XTAL connection diagram.

If we choose to use a frequency source other than a crystal oscillator, such as a TTL

oscillator, it will be connected to XTAL1; the XTAL2 is left unconnected, as shown in fig2.6.

Fig 2.5 XTAL connection to 8051 Fig 2.6 XTAL connection to external clock

signal



2.5.4 RST

Pin 9 is the RESET pin. It is an input and is active high (normally low). Upon applying a high

pulse to this pin, the microcontroller will reset and terminate all the activities. This is often

referred to as power on reset. Activating a power on reset will cause all values in the

registers to be lost. It will set program counter to all 0s. Fig 2.7 shows a power on reset

circuit.

Fig 2.7 Power on RESET circuit

2.5.5 I/O Ports

The four ports P0, P1, P2 and P3 each use 8 pins making them 8 bit ports.

Port 0

Port 0 occupies a total of 8 pins (pins 39-32). It can be used for input or output. As shown

in fig 2.4, port 0 is also designated as AD0-AD7, allowing it to be used for both address and

data. When connecting an 8051 to an external memory, port 0 provides both address and

data. The 8051 multiplexes both address and data through port 0 to save pins. In 8051

based systems where there is no external memory connection, the pins of P0 must be

connected externally to a 10 Ω pull up resistor. This is due to the fact that 0 is an open

drain, unlike the P1, P2 and P3. In contrast to port 0; port 1, port 2 and port 3 do not need

any pull up resistor as they already have pull up resistors internally.



Fig 2.8 Port 0 with pull up resistors

Port 1 and port 2

In 8051 systems with no external memory connection, both the P1 (pins 1-8) and P2 (pins

21-28) are used as simple I/O ports. However in the systems having external memory

connections, port 2 must be used along with P0 to provide the 16 bit address for the

external memory. In that case the P2 is used for the upper 8 bits (A8-A15) of the 16 bit

address, and it cannot be used for I/O.

Port 3

Port 3 occupies a total of 8 pins (10-17). It can be used as input or output. Port 3 has the

additional function of providing some extremely important signal such as interrupts. Table

2.4 provides these alternate functions of P3.

Table 2.4 Alternate functions of port 3

Port 3 bit Function Pin

P3.0 RxD 10

P3.1 TxD 11

P3.2 I T 0 12

P3.3 I T 1 13

P3.4 T0 14

P3.5 T1 15

P3.6 R 16

P3.7 R D 17



P3.0 and P3.1 are used for the RXD and TXD serial communications signal. Bits P3.2 and

P3.3 are set aside for external interrupts. Bits P3.4 and P3.5 are used for timer 0 and mer

1. inally 3.6 and 3.7 are used to pro ide the R and R D signals of external memory

connections. In the systems based on the 8051, P3.6 and P3.7 are used for I/O while the

rest of the pins are normally used in the alternate function role.

2.5.6

E A, which stands for “external access” is pin no. 31 in the DI pac ages. It is an input pin

and must be connected to either Vcc or ground. In other words, it cannot be left

unconnected in the 8051 family mem ers. The E A pin is connected to Vcc in our case.

5

This is an output pin. S E stands for “program store ena le”. This is left unconnected in

8051 microcontroller. This pin remains connected in 8031 based systems.

2.5.8 ALE

“Address latch ena le” is an output pin and is active high. This pin is not used in the 8051

microcontroller.

2.6 Application Concerned Programming

2.6.1 I/O Port Programming

The four ports P0, P1, P2 and P3 are the 8 bit ports. All the ports upon RESET have value

FFH on them and are configured as inputs. They are then ready to be used as input ports.

When the first 0 is written to a port, it becomes an output. To reconfigure it as an input, a

1 must be sent to the port. To use any of these ports as an input port, it must be

programmed by writing 1 to all the bits.

I/O ports and bit addressability

We can access either the entire 8 bits of an I/O port. Or we can access individually 1 bit at

a time. A powerful feature of 8051 I/O ports is their capability to access individual bits of

the port without altering the rest of the bits in that port. In this case we simply use the

syntax “SETB .Y” where is the port num er and Y is the desired it num er (0 to 7) for

data bits D0 to D7. Table 2.5 shows the single bit addressability of the I/O ports of 8051.



P0 P1 P2 P3 Port bit

P0.0 P1.0 P2.0 P3.0 D0

P0.1 P1.1 P2.1 P3.1 D1

P0.2 P1.2 P2.2 P3.2 D2

P0.3 P1.3 P2.3 P3.3 D3

P0.4 P1.4 P2.4 P3.4 D4

P0.5 P1.5 P2.5 P3.5 D5

P0.6 P1.6 P2.6 P3.6 D6

P0.7 P1.7 P2.7 P3.7 D7

Table 2.5 Single bit addressability of I/O ports

2.6.2 Timer Programming

The 8051 has two timers: timer 0 and timer 1. They can be used either as timer or as event

counters. Both timer 0 and timer 1 are 16 bits wide. Since the 8051 has an 8-bit

architecture, each 16-bit timer is accessed as two separate registers of low byte and high

byte.

Timer 0 registers

The 16-bit register of timer 0 is accessed as low byte and high byte. The low byte register is

called TL0 (timer 0 low byte) and the high byte register is referred to as TH0 (timer 0 high

byte). These registers accessed like any other registers, such as A, B, R0, R1, R2 etc. These

registers can also be read like any other registers.

Timer 1 registers

Timer 1 is also a 16 bit register, and it is split into two bytes, referred to as TL1 (Timer 1

low byte) and TH1 (Timer 1 high byte). These registers are accessible in the same way the

as the timer 0 registers.

Fig 2.9 and fig 2.10 show the timer 0 and timer 1 registers respectively.



Fig 2.9 Timer 0 register

Fig 2.10 Timer 1 register

TMOD (Timer mode) register

Both timer 0 and timer 1 use the same register, called TMOD, to set the various timer

operation modes. TMOD is an 8-bit register in which the lower 4 bits are set aside for

Timer 0 and upper 4bits for timer 1. In this case, the lower 2 bits are used to set the timer

mode and the upper 2 bits to specify the operation. Fig 2.8 shows the TMOD register.

Fig 1.11 TMOD register

GATE

In the TMOD register both the timer 0 and timer 1 have the GATE bit. Every timer has a

means of starting and stopping. Some timers do this by software, some by hardware and

some by both hardware and software controls. The timer in the 8051 has both. The start

and stop of the timer are controlled by way of software by the TR (timer start) bits TR0 and

TR1. The SETB instruction starts it, and it is stopped by the CLR instruction. These

instructions start the timers as long as GATE= 0 in the TMOD register. The hardware way of



starting and stopping the timer by an external source is achieved by making GATE= 1 in the

TMOD register.

C/T (Clock/timer)

This bit in the TMOD register is used to decide whether the timer is used as a delay

generator or an event counter. If C/T = 0, it is used as timer for time delay generation. If

the C/T = 1, the TMOD register is used as an event counter. The clock source for the time

delay is the crystal frequency of the 8051. The size of the crystal frequency attached to the

8051 also decides the speed at which the 8051 timer ticks. The frequency for the timer is

always 1/12th of the frequency of the crystal attached to the 8051.Although various 8051

based systems have an XTAL frequency in the range 10 MHz to 40 MHz, we will

concentrate on the XTAL frequency of 11.0592 MHz. The reason behind such an odd

number has to do with the baud rate for serial communication of the 8051.

M0, M1

The M0 and M1 select the timer mode. There are three modes: 0, 1 and 2. Table 2.6

describes the various timer modes. We will concentrate on mode 1 and mode 2 since they

are the ones used most widely. In our case the mode 2 has been used.

M1 M0 Mode Operating mode

0 0 0 13-bit timer mode

8-bit timer/counter THx with TLx as 5-bit

prescaler

0 1 1 16-bit timer mode

16-bit timer/counter THx and TLx are cascaded;

there is no prescaler

1 0 2 8 bit auto reload

8-bit timer/counter; THx holds a value that is to

be reloaded into TLx each time it overflows.

1 1 3 Split timer mode

Table 2.6 Timer modes

TCON register



While the TMOD register controls the timer mode, another register called the TCON

controls the timer/counter operations. The lower four bits of TCON is used for interrupt

functions, and the upper four bits are for timer operations. Fig 2.12 shows the details of

the TCON register.

Fig 2.12 TCON register

Mode 2 programming

The mode 2 operations of the timer are described below.

It is an 8- it timer; therefore it allows only alues of 00 to H to e loaded into the timer’s

register TH.

After TH is loaded with the 8-bit value, the 8051 gives a copy of it to TL. Then the timer is

started. This is done y the instruction “SETB TR0” for timer 0 and “SETB TR1” for timer 1.

After the timer is started, it starts to count up by incrementing the TL registers. It counts

up until it reaches its limit of FFH. When it rolls over from FFH to 00, it sets high the TF

(timer flag). If we are using timer 0, TF0 goes high. If we are using timer 1, TF1 is raised.

When the TL resister rolls from FFH to 00 and the TF is set to 1, TL is reloaded

automatically with the original value kept by the TH register. To repeat the process, we

have to simply clear the TF and let it go without any need by the programmer to reload the

original value. This makes mode 2 auto reload.



Fig 2.13 Mode 2 programming

2.6.3 Serial Port Programming

RxD and TxD pins in the 8051

The 8051 has 2 pins that are used specifically for transferring and receiving data serially.

These two pins are called TxD and RxD and part of the port 3 group (P3.0 and P3.1). Pin 11

of the 8051 (P3.0) is assigned to the TxD and pin 10 (P3.0) is designated as RxD. These pins

are TTL compatible. The serial communication is discussed in the next chapter in details.

In this section we discuss the serial communication registers of the 8051 and how to

program them to transmit and receive data serially. The IBM PC compatible computers are

widely used to communicate with 8051 based systems. To allow data transfer between the

COM port of the PC and an 8051 system without any error, we must make sure that the

baud rates of 8051 matches the aud rate of C’s COM port.

Baud rate in 8051

The 8051 transmit and receive data serially at different baud rates. The baud rate in the

8051 is programmable. This is done with the help of Timer 1.

As discussed in the above section, the 8051 divides the crystal frequency by 12 to get the

machine cycle frequency. In the case of XTAL= 11.0592 MHz, the machine cycle frequency

is 9 1.6 Hz. The 8051’s serial communication UART circuitry di ides the machine cycle

frequency of 921.6 kHz by 32 once more before it is used by the timer 1 to set the baud

rate. This gives 28800 Hz. When the Timer 1 is used to set the baud rate it must be

programmed in mode 2, i.e. 8-bit, auto reload. To get baud rate compatible with the PC,

we must load the TH1 with the values shown in table 2.7.



Baud rate TH1 (Decimal) TH1 (hex)

9600 -3 FD

4800 -6 FA

2400 -12 F4

1200 -24 E8

Table 2.7 The Timer 1 TH1 register values for different baud rates

Fig 2.14 setting the frequency

SBUF Register

SBUF is an 8-bit register used solely for serial communication in the 8051. For a byte of

data to be transferred via the TxD line, it must be placed in the SBUF register. The moment

a byte is written into the SBUF, it is framed with the start and stop bits and transferred

serially via the TxD pin. Similarly, SBUF holds the byte of data when it is received by the

8051’s RxD line. The 8051 deframes the its y eliminating the stop and start its and then

placing it in the SBUF. The SBUF can be accessed like any other registers in the 8051.

SCON (Serial control) register

The SCON register is an 8-bit register used to program the start bit, stop bit and data bits

of data framing. Fig 2.12 shows the various bits of the SCON register.

Fig 2.15 SCON register



SM0, SM1

SM0 and SM1 are D7 and D6 of the SCON register, respectively. That is, SCON.7 and

SCON.6 (since SCON is bit addressable). These two bits determine the framing of data by

specifying the number of bits per character, and the start and stop bits. They take the

following combinations:

SM0 SM1 Modes

0 0 Serial mode 0

0 1 Serial mode 1, 8-bit data, 1 stop bit and 1 start bit

1 0 Serial mode 2

1 1 Serial mode 3

Table 2.8 serial communication modes

Of the 4 serial modes, only mode 1 is of interest of us. In the SCON register when serial

mode 1 is chosen, the data framing is 8 bits, 1 start bit and 1 stop bit. This makes it

compatible with the COM port of the PC. Most importantly, serial mode 1 allows the baud

rate to be variable and set by Timer 1 of 8051.

SM2

SM2 is the D5 of the SCON register (SCON.5). This bit enables the multiprocessing

capability of the 8051.

REN

The REN (receive enable) bit is D4 of the SCON register (SCON.4). When this bit is high, it

allows the 8051 to receive data on the RxD pin. As a result if we want the 8051 to both

transfer and receive data, the REN must be set to 1. By making REN= 0, the receiver is

disabled.

TB8

TB8 (transfer bit 8) is bit D3 of the SCON (SCON.3). It is used for serial modes 2 and 3.

RB8



RB8 (transfer bit 8) is the bit D2 of the SCON (SCON.2). In serial mode 1 this bit gets a copy

of the stop bit when an 8-bit data is received. In our application we will make RB8 = 0 as

this bit is rarely used anymore.

TI

TI (transmit interrupt) is the bit D1 (SCON.1) and an extremely important flag bit in the

SCON register. When the 8051 finishes the transfer of 8-bit character, it raises the TI flag to

indicate that it is ready to transfer another byte. The TI bit is raised at the beginning of the

stop bit.

RI

RI (receive interrupt) is the bit 0 (SCON.0) of the SCON register. When the 8051 receive

data serially via RxD, it places the byte in the SBUF register. Then it raises the RI flag bit to

indicate that a byte has been received and should be picked up before it is lost. The RI is

raised halfway through the stop bit.

Programming the 8051 to transfer data serially

In programming the 8051 to transfer character bytes serially, the following steps are

taken:

1. The TMOD register is loaded with the value 20H, indicating the use of Timer 1 in mode

2 (8-bit auto reload) to set baud rate.

2. The TH1 is loaded with one of the values in the table 2.7 to set the baud rate for serial

data transfer (assuming XTAL= 11.0592 MHz).

3. The SCON register is loaded with the value 50H, indicating serial mode 1, where an 8

bit data is framed with start and stop bit.

4. TR1 is set to 1 to start the timer 1.

5. TI bit is cleared.

6. The character byte to be transferred serially is written into the SBUF register.

7. The TI bit is monitored to see if the character has been transferred completely.

8. To transfer the next character, we go to step 5.



Programming the 8051 to receive data serially

The steps 1-4 given in the programming of 8051 to transfer data serially are followed.

1. The RI bit is cleared.

2. The RI flag is monitored to see if an entire character has been received yet.

3. When RI is raised, SBUF has the byte. Its contents are moved into a safe place.

4. To receive the next character we go to the step 2.

2.6.4 Interrupt Programming

Interrupts vs. Polling

A single microcontroller can serve several devices. There are two ways to do that:

interrupts and polling. In the interrupt method, whenever any device needs its service, the

device notifies the microcontroller by sending it an interrupt signal. Upon receiving the

interrupt signal, the microcontroller interrupts whatever it is doing and serves the device.

The program associated with the interrupt is called the interrupt service routine (ISR) or

the interrupt handler. When an interrupt is invoked, the microcontroller runs the ISR. In

polling, the microcontroller continuously monitors the status of a given device. When the

status condition is met, it performs the service. After that it moves on to monitor the next

device until each one is serviced. The interrupt method is preferable in case of the 8051

microcontroller.

Steps in executing an interrupt

Upon activating an interrupt, the microcontroller goes through the following steps:

1. It finishes the instruction it is executing and saves the address of the next

instruction (PC) on the stack.

2. It also saves the current status of all the interrupts internally (i.e., not on the stack).

3. It jumps to a fixed location in the memory called the interrupt vector table that

holds the address of the interrupt service routine.



4. The microcontroller gets the address of the ISR from the interrupt vector table and

jumps to it. It starts to execute the interrupt service subroutine until it reaches the

last instruction of the subroutine, which is the RETI (return from interrupt).

5. Upon executing the RETI instruction, the microcontroller returns to the place

where it was interrupted. First it gets the program counter (PC) address from the

stack by popping the top two bytes of the stack into the PC. Then it starts to

Execute from that address.

Enabling and disabling an interrupt

Upon reset all interrupts are disabled, meaning that none will be responded to by the

microcontroller to respond to them. There is a resister called IE (interrupt enable) that is

responsible for enabling (unmasking) and disabling (masking) the interrupts. It is a bit

address register. Fig 2.13 shows the IE register.

Fig 2.16 IE (interrupt enable) register

The bit D7 in the IE register is called EA (enable all). This must be set to 1 to allow the rest

of the register to take effect. If EA=1, interrupts are enabled and will be responded to if

their corresponding bits in IE are high. If EA=0, no interrupt will be responded to, even if

the associated bit in the IE register is high.

Six interrupts in the 8051

Reset: when the reset pin is activated, the 8051 jumps to the address 0000 (power up

reset).

Timer 0 (TF0) and timer 1 (TF1) interrupt: Memory location 000BH and 001BH in the

interrupt vector table belongs to these interrupts, respectively.

External hardware interrupt 0 (INT0) and External hardware interrupt (INT1): Pin

numbers 12 (P3.2) and 13 (P3.3) in port 3 are for INT0 (EX1) and INT1 (EX2) respectively.

Memory locations 0003H and 0013H in the interrupt vector are assigned to the INT0 and

INT1 respectively.



Serial COM interrupt: Serial communication has a single interrupt that belongs to both

receive and transmit. The interrupt vector table location 0023H belongs to this interrupt.

Interrupt priority in 8051

When the 8051 is powered up, the priorities are assigned according to the table 2.9.

Highest to lowest priority

Interrupt ROM location of ISR Pin

Reset 0000 9

External Interrupt 0 (INT0) 0003 P3.2 (12)

Timer interrupt 0 (TF0) 000B --

External interrupt 1 (INT1) 0013 P3.3 (13)

Timer interrupt 1 (TF1) 0013 --

Serial communication (RI+TI) 0023 --

Table 2.9 8051 Interrupt priorities

Programming the serial communication interrupt

As far as serial communication is concerned, the concept of transmitting and receiving

data as discussed in the above section applies equally when using either polling or

interrupt. The only difference is how the serial communication needs are served. In polling

method, we wait for the flag (TI or RI) to be raised; while we cannot do anything else. In

the interrupt method we are notified when the 8051 has received a byte or is ready to

send the next byte. We can do other things while the serial communication needs are

served.

In the vast majority of applications, the serial interrupt is used mainly for receiving data

and never used for sending data serially. Since there is only one interrupt for both receive

and transmit, the ISR clears the RI and TI flags before executing the RETI instruction.



3. Serial Communication

Microcontroller communicates with other peripheral devices or microcontroller in the

form of serial or parallel technique. In parallel procedure the entire byte of data is

transmitted at a time from transmitting device to receiving device. This technique is

favorable for short distance and requires separate lines for each bit to transmit. While

serial communication, a single bit is transmitted at a time and once eight bits are received

at the recei er’s end the data yte is reconstructed. Although it requires time to transmit

and receive data byte but it useful in long distance transmission.

3.1 Asynchronous versus synchronous serial transmission

In serial communication, the transmitting and receiving devices need to be in

synchronization to follow common protocol and data rate. Synchronization helps

transmitter and receiver to expect data transmission/reception at same time. There are

two ways to have synchronization between transmitter and receiver: Asynchronous and

Synchronous.

In an Asynchronous serial communication system, such as USART abroad ATmega16,

framing bits are used at the beginning and end of a data byte. These framing bits alert the

receiver that an incoming data byte has arrived and also signals the completion of the data

byte reception. The data rate for an asynchronous serial system is typically much slower

than the synchronous system, but it only requires a single wire between the transmitter

end the receiver.

A synchronous serial communication system maintains synchronize between the

transmitter and receiver by employing a common clock between the two devices. Data

byte are sent and received at the edge of the clock. This allows data transfer rates higher

than with asynchronous techniques but requires two lines: data and clock to connect

transmitter and receiver.

3.2 Baud rate

The transmission rates of data are typically specified as baud or bits per second rate. For

example, 9600 baud indicates data are being transferred at 9600 bits per second.

3.3 Duplex



Duplex is the term used for communication system that defines the hardware used for

transmission and reception.

In simplex the data transmitted to the receiver from transmitter. Whereas in half duplex

data is transmitted in one way at a time. While in full duplex data can move both ways at a

time.

Fig 3.1: Transmission of data using Duplex.

3.4 UART

Many manufacturers make special IC chips for serial communications: UART (Universal

Asynchronous Receiver-Transmitter) & USART (Universal Synchronous-Asynchronous

Receiver-Transmitter).

UARTs are used for serial communication between systems; they can be either half duplex

(send or receive) or full duplex (send and receive at the same time). Also known as an

RS232 connection the microcontroller UART can provide the connection with a PC or

another microcontroller-based system. Figure 3.2 illustrates possible connection

arrangements. In a minimum connection there could be only two transmission lines,

transmit (Tx) and receive (Rx) as shown in Figure 3.3. The data is conveyed as a bit stream,

either transmit or receive, and the speed is defined by the baud rate i.e. the bits per

second.

The UART has four mode of operation, 0 to 3. Modes 0 and 2 have fixed baud rates, mode

0 is one-sixth of the oscillator frequency, and mode 2 is 1/16 or 1/32 of the oscillator

frequency. For modes 1 and 3 the baud rate can be selected, a typical range is:



75, 150, 300, 600, 1200, 2400, 4800, 9600, 19200, 38400

Modes 0 and 1 are used for connection between two devices. Modes 2 and 3 are used for

master slave multiprocessor systems, in principle there could be one master

microcontroller and up to 255 slave microcontrollers.

Fig 3.2: Use of RS-232 interface between PC and microcontroller or between two

microcontrollers.

Fig 3.3: RS-232 transmits (Tx) and receives (Rx) connections between a PC and

Microcontroller.

3.5 RS-232



RS-232 is the traditional name for a series of standards for serial binary single-ended data

and control signals connecting between a DTE (Data Terminal Equipment) and a DCE (Data

Circuit-terminating Equipment). It is commonly used in computer serial ports. The

standard defines the electrical characteristics and timing of signals, the meaning of signals,

and the physical size and pin out of the connectors. RS-232 establishes two-way (Full

duplex) communications, with signals represented by voltage levels measured with respect

to a system common ground. The “idle” state (MARK) is negati e with respect to common

ground and the ‘acti e” state (S ACE) is positi e with respect to common ground.

Fig 3.4: Format of data byte transmission.

The transmission of the data byte starts with start bit which is always low (0) and ends

with stop bit(s) which always high (1). The LSB follow the start bit and MSB is followed by

stop bit as shown in fig 3.4. In order to maintain data integrity, the parity bit is introduced

in the data frame.

The standard output signal level of RS-232 usually varies between -12V and +12V, with a

“dead region” etween +3 and -3V designed to absorb line noise. The TTL signal voltage

from UART is between 0 and 5 volts, but after being transformed by the RS-232

transceiver, the signal voltage is changed to +12V to -12V.

3.6 Max-232

Max 232 is an integrated circuit that converts signals from a RS-232 serial port to signals

suitable for use in TTL compatible digital logic circuits. Max 232 is a dual driver/receiver

and typically converts the Rx, Tx, CTS and RTS signals.



The drivers provide RS-232 voltage level outputs (approx. ± 7.5 V) from a single +5 V supply

via on-chip charge pumps and external capacitors. This makes it useful for implementing

RS-232 in devices that otherwise do not need any voltages outside the 0 V to +5 V range,

as power supply design does not need to be made more complicated just for driving the

RS-232 in this case.

The receivers reduce RS-232 inputs (which may be high as ± 25V), to standard 5 V TTL

levels. These receivers have a typical threshold of 1.3 V, and a typically hysteresis of 0.5 V.

Fig 3.5: Block diagram of Max-232 and its connection.

3.7 Conclusion

The serial communication emerges as an important protocol in the arena of

communication with hit and misses. It is favourable for long distance and cost effective

with less number of connecting wires and one of the commonly used forms of

communication.



4. RF Switch

A switch is an electrical component that can break an electrical circuit, interrupting the current or

diverting it from one conductor to another. The most familiar form of switch is manually operated

electromechanical device with one or more sets of electrical contacts, which are connected to

external circuits.

Switches are classified according to the arrangement of their contacts in electronics. A pair of

contacts is said to e “closed” when current can flow from one to the other. hen the contacts are

separated y an insulating air gap, they are said to e “open”, and no current can flow etween

them at normal oltages. The terms “ma e” for closure of contacts and “ rea ” for opening of

contacts are also widely used.

In a push button type switch, in which the contacts remain in one state unless actuated, the

contacts can either be normally open until closed by operation of the switch, or normally closed

and opened by the switch action. A switch with both types of contact is called changeover switch.

These may e “ma e-before- rea ” which momentarily connect oth circuits, or may e “ rea -

before-ma e” which interrupts one circuits efore closing the other.

4.1 Pole and Throw

The terms “pole” and “throw” are also used to descri e switch contact ariations. The num er of

“poles” is the num er of separate circuits which are controlled y a switch. or example, a “ -

pole” switch has two separate identical sets of contacts controlled y the same knob. The number

of “throws” is the num er of separate position that the switch can adopt. A single throw switch

has one pair of contacts that can either be closed or open. A double throw switch has a contact

that can be connected to either of two other contacts; a triple throw has a contact which can be

connected to one of three other contacts, etc. These term gives rise to abbreviation for the types

of switch which are used in the electronics industry such as “single-pole, single-throw” (S ST) (the

simplest type, “on or off”) or “single-pole, double-throw” (S DT), connecting either of two

terminals to the common terminal. Switches with large numbers of poles or throws can be

descri e y replacing the “S” or “D” with a num er (e.g. 3 ST, 4 ST, etc.) or in some cases the

letter “T” (for “triple”).

Fig 4.1: Representation of SPST, SPDT, DPST, DPDT



4.2 Switch Matrix

The Switch Matrix is made up of switches and signal conditioners that are mounted

together in a mechanical infrastructure or housing. It is used in test systems, in both

design verification and manufacturing test, to route high frequency signals between the

device under test (DUT) and the test and measurement equipment. Besides signal routing,

the switch matrix may also contain signal conditioning including passive signal devices

such as attenuators, filters, and directional couplers, as well as active signal conditioning,

such as amplification and frequency converters. Since the signal routing and conditioning

needs of a test system differ from design to design, switch matrices need to be custom

designed by the custom test engineer for each new system.

Fig 4.2: Application of switch matrix.

4.3 ZASW-2-50DR

It is a SPDT in which we apply control signal through TTL IN to select either of the RF OUT 1 or RF

OUT 2. The control signal can be in high (logic 1) or low (logic 0) depending on which one of the RF

out line will be selected. Moreover it is also a TTL driver.



Fig 4.3: Block representation of ZASW-2-50 DR switch matrix.

Fig 4.4: Truth table of control signal for selection of RF OUT(s).

4.4 ZSWA-4-30-DR

It is a SP4T switch in which a single signal is routed to as many four ways with the help of four

control signals. It is a TTL driver.



Fig 4.5: Block representation of ZSWA-4-30 DR switch.

Fig 4.6: Truth table of ZSWA-4-30 DR switch.

4.5 Switch Matrix

We used a switch matrix constructed with ZASW-2-50 DR and ZSWA-4-30 DR switch. The

control signals to the switches are generated by the microcontroller that enables selection

of antenna connected at the end of switches.

4.6 Conclusion

The switch plays an important role in the routing of signal from one end to other. It acts as a

medium for efficient and better signal transmission and helps to maintain signal integrity.



5. Design of the control Circuit

5.1 The schematic

The schematic of the control circuit is designed using OrCAD capture and is provided in

appendix A. The OrCAD project file is included along with the soft copy the report.

5.2 Description of the circuit blocks

5.2.1 The 8051 microcontroller

It is the heart of the control circuit. The microcontroller is pre-programmed to receive

control word from PC via its serial ports and then manipulate the word and sending the

control signals to the switch matrix from its parallel I/O ports. The microcontroller is

equipped with 11.0592 MHz crystal, reset switch (push button), Pull up resistors for P0.

5.2.2 The Max3232 chip

As mentioned earlier in microcontroller 8051 uses TTL logic levels, but PC port uses RS232

standard. To overcome this mismatch the max3232 chip is used in the serial

communication path. It takes rs232 standard as input from PC and generates a TTL level

output for the microcontroller and vice versa in the alternate path (TTL to RS232).

5.2.3 The 7408 chips

It is the buffer block of the circuit used for driving LED. The I/O ports of 8051

microcontroller can sink current upto 1.6 mA (3.2 mA for port0). This current cannot drive

LED’s. Therefore 7408 chips are installed in etween the ports and the LED’s. It sinks

current upto 0 mA which is recommended for LED’s to glow with full rightness.

A 7408 chips comprises of four 2-input and gates, here we are connecting one port output

line to one input of a logic gate; the other input is predefined to be high. Thus the port pin

status appears at the output. Following figure shows 7408 pin configuration and logic

table.



Fig 5.1 7408 pin configuration

Fig 5.2 7408 truth table

Another important role of these chips is to act as protection circuit for the switch

matrix. The control signals should not be fed to the switches unless Vcc supply is

provided to them. This can be achieved by connecting the +5v supply to the predefined

logic inputs of the 7408 gates through a switch.

5.2.4 The LED arrays

There are 3 arrays of LED each consisting of 8 LED’s is connected to port 0, port1, and

port2 of the microcontroller. These arrays work as display device and permit us to

chec weather proper control signal is eing generated or not. The LED’s are in

common cathode connection and a current limiting resistor of 330 Ohms is connected

to each.

5.2.5 The DB9 connectors

There are four 9 pin D type connector in the circuit, one of them is used to connect

with the PC whereas the other three corresponds to the three ports (P0, P1, P2) of the

microcontroller and used to drive the control signal to the switch matrix.



5.2.6 Other components

All the other components especially capacitor are inserted within the board as

required by the different chips for proper operation. Also for each IC a de-coupling

capacitor is used to avoid damaging of the IC.

5.2.7 Test points

The test points TP1 & TP2 is installed to provide +5V Vcc and ground supply

respectively.

5.3 The Final Design

The final SWITCH MATRIX CONTROLLER board after installing all the components is

provided in fig 5.3 below.

Fig 5.3 the final circuit board in PCB



6. Programming the Microcontroller

6.1 Introduction

A microcontroller is useless without a program burned to it. It must know the

executable instructions to perform after startup. The executable hex file is to be fused

to a microcontroller before installing it to the circuitry. Keil uVision is the software tool

that is used to create the fusable hex file of our required program.

The program needed for the switch matrix controller is written in C code and compiled

using keil. The hex file is created and is fused to the 8051 chip with an IC programmer.

6.2 The flowchart

Fig 6.1 the programming flowchart



6.3 Programming steps

The microcontroller is required to program so that it can generate control signal for a

switch matrix that is controlling eight antennas among which four are transceiver and

other four are dedicated receiver. The programming steps are explained below.

6.3.1 Programming the serial port

To enable the microcontroller for serial communication with required baud rate (9600)

the SCON, TMOD, TH registers are initialized. A table for the initial values is shown below.

Register SCON TMOD TH

Value 50h 20h FDh

Table6.1 registers values for serial port programming

6.3.2 Decoding control word

To decode the 8 control word we must know its format. As mentioned earlier it is a 8 bit

word upper nibble comprising of Txr code and lower nibble comprising of Rxr code. From

the received value Txr/Rxr codes are achieved with shifting and masking operations as

follows.

Txcode=conword && 0xF0; Txcode=Txcode>>4; Rxcode=conword && 0x0F;

6.3.3 Generating control signals

After decoding Txr and Rxr code the control signal is to be generated by making certain

bits of the I/O ports high/low accordingly. A configuration for port bits to switch matrix is

made as shown in fig 6.2



Fig 6.2 Arrangement of switch antenna along with port bit connection to the control

lines

The next step in control signal generation is to determine the control bits to be cleared

according to Txr/Rxr code. Following tables are provided for this.

TABLE: Transmitter selection

Code Antenna to be

selected

Bits status

0000 A0 P0.0=0; P0.4=0; others 1

0001 A1 P0.1=0; P0.5=0;others 1

0010 A2 P0.2=0; P0.6=0;others 1

0011 A3 P0.3=0;P0.7=0;others 1

Table 6.2 Port bit status for Transmitter selection



TABLE: Receiver selection

Code Antenna to be

selected

Bits status

0000 A0 P1.0=0; P2.0=0; others 1

0001 A1 P1.1=0; P2.0=0;others 1

0010 A2 P1.2=0; P2.0=0;others 1

0011 A3 P1.3=0; P2.0=0;others 1

0100 A4 P1.4=0; others 1

0101 A5 P1.5=0; others 1

0110 A6 P1.6=0; others 1

0111 A7 P1.7=0; others 1

Table 6.3 port bit status for Receiver selection

6.4 The complete code

The C code written in keil environment is provided below.

/* C code for switch matrix controller */ #include<regx51.h> #include<stdio.h> unsigned char conword; void receive(); void transmit(); void main() unsigned char txcode; unsigned char rxcode; TMOD=0x20; TH1=0xFD; SCON=0x50; TR1=1; while(1)



receive(); P0=0xff; P1=0xff; P2=0xff; rxcode=conword & 0x0f; txcode=conword & 0xf0; txcode=txcode>>4; switch(txcode) case 0: P0_0=0; P0_4=0; break; case 1: P0_1=0; P0_5=0; break; case 2: P0_2=0; P0_6=0; break; case 3: P0_3=0; P0_7=0; break; default: P0=0xff; P1=0xff; P2=0xff; switch(rxcode) case 0: P1_0=0; P2_0=0; break; case 1: P1_1=0; P2_0=0; break; case 2: P1_2=0; P2_0=0; break; case 3: P1_3=0; P2_0=0;



break; case 4: P1_4=0; P2_0=1; break; case 5: P1_5=0; P2_0=1; break; case 6: P1_6=0; P2_0=1; break; case 7: P1_7=0; P2_0=1; break; default: P0=0xff; P1=0xff; P2=0xff; transmit(); void receive() while(RI==0); conword=SBUF; RI=0; void transmit() SBUF=conword; while(TI==0); TI=0; /*End of File*/



6. Conclusion

The project wor “switch matrix controller” is used for experimental use of the radar system.

In case of real field application, for switching of antennas the controller is designed through

FPGA (field programmable gate arrays). The features of the microcontroller based control

circuit designed throughout the project is listed below.

1. Serial communication

The control circuit is can communicate with PC via its serial UART. Thus the control word

from PC is received serially and it can send acknowledgement to the PC in the same

manner

2. Fast decoding

Microcontroller being a fast device decodes the control word and generates the control

signals within a few milliseconds.

3. On board LED

The control circuit comprise of LED arrays corresponding to each output line. Thus we can

check whether the controller is working properly or not by means of the status of the

LED’s.

4. Number of output lines

The circuit provides a maximum of 24 output lines that can be used as control signals to

the switch matrix.

5. Driver cum protection circuit

The buffer block in the controller comprises of 7408 IC’s. This loc acts as LED dri er as

well as a protection circuit for the switch matrix.

The circuit however cannot work independently. It must receive a control byte from PC to

generate control signals for the switch matrix. Therefore we need a control word generator in

our PC that will send the control words in the format specified to the microcontroller. A

matlab GUI can be used for this purpose.





Appendix B THE ORCAD Overview OrCAD is a proprietary software tool suite used primarily for electronic design automation. The software is used mainly to create electronic schematics and electronic prints for manufacturing printed circuit oards ( CB’s).

The name OrCAD reflects the company and its software's origins: Oregon + CAD; Founded in 1985 y John Dur eta i, Ken and Keith Seymour as “OrCAD Systems Corporation” in Hills oro, Oregon. The company became a leading worldwide supplier of desktop electronic design automation (EDA) software. The company’s first product was SDT (schematic design tools). It passes through several stages of development and upgradation and finally OrCAD product line has been fully owned by Cadence Design Systems in 1999.

OrCAD Capture provides fast and intuitive schematic design entry for PCB development or analog simulation using PSpice. The component information system (CIS) integrates with it to automatically synchronize and validate externally sourced part data. OrCAD Capture CIS integrates the OrCAD Capture schematic design application with the added capabilities of a component information system (CIS) and the Cadence ActiveParts Portal.

CIS allows designers to search, identify, and populate the design with preferred parts. With easy access to company component databases and part information, designers can reduce the amount of time spent researching needed parts.

The PSpice allows simulation environment for the designs.

Products Capture CIS

OrCAD PCB Editor

PSpice

Layout Plus

Features/Benefits

Boosts schematic editing efficiency of complex designs through hierarchical and variant design capabilities

Integrates with a robust CIS that promotes the use of preferred, current parts to accelerate the design process and reduce project costs

Provides access to more than two million parts with Cadence ActiveParts, offering greater flexibility when choosing design components.



Appendix C The Keil uVision Overview Keil was founded in 1982 by Günter und Reinhard Keil, initially as a German GbR. In April 1985

the company was converted to Keil Elektronik GmbH to market add-on products for the

development tools provided by many of the silicon vendors. Keil implemented the first C

compiler designed from the ground-up specifically for the 8051 microcontroller.

Keil provides a broad range of development tools like ANSI C compiler, macro assemblers,

debuggers and simulators, linkers, IDE, library managers, real-time operating systems and

evaluation boards for 8051, 251, ARM, and XC16x C16x ST10 families.

Popular Products

8051 Development Tools

Keil C51 is the industry-standard tool chain for all 8051-compatible devices, it supports classic 8051, Dallas 390, NXP MX, extended 8051 variants, and C251 devices. The µVision IDE/Debugger integrates complete device simulation, interfaces to many target debug adapters, and provides various monitor debug solutions.

C166 Development Tools

Keil C166 development tools support the Infineon C166, XC166, XE166, XC2000 and ST10 microcontroller families. The µVision IDE/Debugger interfaces to the Infineon DAVE code generation tool and various debug solutions including the ULINK2.

Evaluation Boards

Keil offer an extensive range of evaluation boards and starter kits to quick start your development. Boards are available for ARM, 8051, and 166 processor-based devices.

µVision IDE and Debugger

The Keil µVision4 IDE is common to all Keil software development tools.

The uVision IDE

The µVision IDE from Keil combines project management, make facilities, source code editing, program debugging, and complete simulation in one powerful environment. The µVision

http://www.keil.com/c166/

http://www.keil.com/boards/

http://www.keil.com/uvision/



development platform is easy-to-use and helping you quickly create embedded programs that work. The µVision editor and debugger are integrated in a single application that provides a seamless embedded project development environment.

Project Concerned Use

In our project keil uvision IDE 4 is used to write the C code for the controller. Debug the code and create the hex file to fuse into the microcontroller.



Appendix D

About the organization: LRDE is one of the R&D Establishments set up under the Defence of Research & Development Organization to address the Services needs in the field of RADAR, Communication Systems and related technologies. In 1962, Electronics Research and Development Establishment was renamed as Electronics & Radar Development Establishment (LRDE). The scope of the laboratory was changed to emphasize the greater importance for indigenous development of RADAR and Communication Systems. LRDE has made very significant contributions towards Design and development of complex Military Electronic Systems, Communication and RADARs, which are serving our Armed Forces. LRDE has the Core Competence and Expertise to build world class RADAR systems and Software driven electronic Systems.

Vision of LRDE To create a centre of excellence in design and development of RADARs and related Technologies.

Mission of LRDE 1. To design and develop Radar systems and related technologies to cater to the Needs of Services. 2. To contribute towards the enhancement of the infrastructure, knowledge Base and technologies for achieving self-reliance. 3. To promote research and competence building activities in the field of RADAR Within the laboratory and in the academic institutions and continuously evolve as the centre of excellence in RADAR technology.

Quality Policy LRDE is committed to the indigenous development of modern RADAR systems through an effective quality management system.

Quality Objectives 1. Develop modern RADAR systems to meet user requirements. 2. Enhance capabilities in technologies and systems engineering. 3. Implement quality management system and enhance quality through continual improvement.

Organization Areas of Work & Achievements Design and Development of Radar Systems

Army - Multifunction Phased Array Radar and 3D Surveillance Radar for Akash Missile Weapon System - Low Level 2D Radar for Fire Control and Air Defence - Short Range Battle Field Surveillance Radar - Weapon Locating Radar



-3D Tactical Control Radar

Air Force - Multifunction Phased Array Radar and 3D Surveillance Radar for Akash Missile Weapon

System - Active Phased Array Radar for AEW&C - Low level 2D radar and 3D Short & Medium Range Surveillance Radar For Air Defence - Medium Power Radar (MPR) - Low Level Transportable Radar (LLTR) - Active Electronically Scanned Array Radar (AESA)

Navy - Maritime Patrol Radar for fixed and Rotary Wing Aircraft

- Maritime Patrol Radar with SAR & ISAR - 3D Medium Range Surveillance Radar for ASW Corvettes

Development of Radar Technologies - Antennae: Slotted Waveguide, Patch Array & Multibeam Antenna - T/R Modules and Active Aperture Arrays - Programmable DSP - Radar Data Processors - High Average Power TWT based Transmitters - High purity sources - Multi-channel double heterodyne receivers



BIBLIOGRAPHY

BOOKS:

Introduction to RADAR systems, 3rd edition, Merril L. Skolink

The 8051 Microcontroller and Embedded systems using assembly and C, 2nd edition;

Mazidi, Mazidi & McKinlay

ONLINE REFERENCES

http://en.wikipedia.org/wiki/Radar

http://en.wikipedia.org/wiki/RS-232

http://en.wikipedia.org/wiki/MAX232

http://en.wikipedia.org/wiki/Intel_MCS-51

HTTP://NPTEL.IITM.AC.IN/COURSES/WEBCOURSE-CONTENTS/IIT-KANPUR/MICROCONTROLLERS

http://en.wikipedia.org/wiki/RF_switch_matrix

http://en.wikipedia.org/wiki/Serial_communication

http://en.wikipedia.org/wiki/OrCAD

http://en.wikipedia.org/wiki/Keil_%28company%29

http://www.keil.com/products

www.cadence.com/products/orcad/orcad_capture

DATASHEETS AND USER GUIDES

AT89C51 datasheet by ATMEL

MAX3232 datasheet by MAXIM

7408 datasheet by PHILIPS

ZSWA-4-30DR

ZASWA-2-50DR/DR+

OrCAD® Capture USER GUIDE by Cadence Design Systems

μVision®4 Getting Started Guide by keil

http://en.wikipedia.org/wiki/Radar

http://en.wikipedia.org/wiki/RS-232

http://en.wikipedia.org/wiki/MAX232

http://en.wikipedia.org/wiki/Intel_MCS-51

http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-KANPUR/microcontrollers

http://en.wikipedia.org/wiki/RF_switch_matrix

http://en.wikipedia.org/wiki/Serial_communication

http://en.wikipedia.org/wiki/OrCAD

http://en.wikipedia.org/wiki/Keil_%28company%29

http://www.keil.com/products

http://www.cadence.com/products/orcad/orcad_capture

Documents

Switch matrix Controller