Embedded c lab and keil c manual

CENTURION UNIVERSITY OF TECHNOLOGY AND
MANAGEMENT
2014-2015
EMBEDDED C LAB
MANUAL
E.C.E DEPARTMENT
PREPARED BY :
K HARI KRISHNA
C E N T U I O N U N I V E R S I T Y O F T E C H N O L O G Y A N D M A N A G E M E N T
A L L U R I N A G A R , P A R L A K H E M U N D I

1
INDEX
S.NO CONTENTS PAGE NO.
1 Introduction to Keil micro vision software. 2-22
2 C Program to print hello world. 23-37
3 C program to store the data in the accumulator. 38-46
4 C Program to send values 00-ff to Port 1. 47-48
5 C Program to send hex values for ASCII characters 0, 1,
2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f to port 1.
49-50
6 C program to toggle all the bits of P1 continuously. 51-52
7 C program to toggle bit D0 of port 1 50,000 times. 53-54
8 C program to generate a square wave for 1ms delay. 55-57
9 C program to send the data serially. 58-59
10 C program to receive the data serially. 60-62
11 C program to convert packed BCD 0x29 to ASCII and
Display the bytes on P1and P2.
63-64
12 C program to convert the hex to decimal and display the
digits on P0, P1, and P2.
65-66

2
Experiment-1
Introduction to Keil:-
Embedded system means some combination of computer hardware and
programmable software which is specially designed for a particular task
like displaying message on LCD. It involves hardware (8051 microcontroller) and
software (the code written in assembly language).
Some real life examples of embedded systems may involve ticketing machines,
vending machines, temperature controlling unit in air conditioners etc.
Microcontrollers are nothing without a Program in it.
One of the important part in making an embedded system is loading the
software/program we develop into the microcontroller. Usually it is called “burning
software” into the controller. Before “burning a program” into a controller, we must
do certain prerequisite operations with the program. This includes writing the
program in assembly language or C language in a text editor like notepad, compiling
the program in a compiler and finally generating the hex code from the compiled
program. Earlier people used different software’s /applications for all these 3 tasks.
Writing was done in a text editor like notepad/ WordPad, compiling was done using
a separate software (probably a dedicated compiler for a particular controller like
8051), converting the assembly code to hex code was done using another software
etc. It takes lot of time and work to do all these separately, especially when the task
involves lots of error debugging and reworking on the source code.
The µVision IDE is the easiest way for most developers to create embedded
applications using the Keil development tools. The new Keil µVision4 IDE has been
designed to enhance developer's productivity, enabling faster, more efficient
program development.
Keil MicroVision is a free software which solves many of the main points for an
embedded program developer. This software is an integrated development
environment (IDE), which integrated a text editor to write programs, a compiler and
it will convert your source code to hex files too. µVision4 introduces a flexible
window management system, enabling us to drag and drop individual windows
anywhere on the visual surface including support for Multiple Monitors.

3
Embedded Systems Vs General Computing Systems
C51 Development Tools
Keil development tools for the 8051 microcontroller family support every level of
developer from the professional applications engineer to the student just learning
about embedded software development. The industry-standard Keil C Compilers,
Macro Assemblers, Debuggers, Real-time Kernels, and Single-board Computers
support ALL 8051-compatible derivatives and help you get your projects completed
on schedule.
The following table shows the Keil C51 Product Line (across the top) and the
Components that are included (along the left side). You may use this information to
find the development tool kit that best fits your needs.

4
Introduction
The C51 development tool chains are designed for the professional software
developer, but any level of programmer can use them to get the most out of the 8051
microcontroller architecture.
With the C51 tools, embedded applications can be generated for virtually every 8051
variant. Refer to the µVision Device Database for a list of currently supported
microcontrollers.
This introduction includes a brief explanation of the:
 Software Development Cycle that describes the steps and tools involved to
create a project.
 Development Tools that describes the major features of the Keil C51
development tools including the µVision IDE and Debugger.
 Folder Structure that describes the default location of µVision and the C51
tool chain installation
Development Tools
The Keil C51 development tools offer numerous features and advantages that help
you to develop embedded applications quickly and successfully. Find out more about
the supported devices and the possible tool combinations available for the different
8051 variants.
The following block diagram shows the components involved in the build process.
The µVision IDE is a window-based software development tool that combines
project management and a rich-featured editor with interactive error correction,
option setup, make facility, and on-line help. Use µVision to create source files and
organize them into a project that defines your target application.

5
µVision Integrated Development Environment (IDE)
C Compiler
The Keil Cx51 Compiler is a full ANSI implementation of the C programming
language and supports all standard features of the C language. In addition, numerous
extensions have been included to directly support the 8051 and extended 8051
architecture.
Macro Assembler
The Keil Ax51 Macro Assembler supports the complete instruction set of the 8051
and all 8051 derivatives.
Library Manager
The LIBx51 Library Manager allows you to create the object library from object
files created by the compiler and assembler. Libraries are specially formatted,
ordered program collections of object modules that may be used by the linker at a
later time. When the linker processes a library, only those object modules necessary
to create the program are used.
Linker/Locater
The Lx51 Linker/Locater creates the final executable 8051 program and combines
the object files created by the compiler or assembler, resolves external and public
references, and assigns absolute addresses. In addition, it selects and includes the
appropriate run-time library modules.

6
µVision Debugger
The µVision Debugger is ideally suited for fast and reliable program debugging. The
debugger includes a high-speed simulator capable of simulating an entire 8051
system including on-chip peripherals and external hardware.
The µVision Debugger provides several ways to test programs on target hardware:
 Use the Keil ULINK USB-JTAG adapter for downloading and testing
your program.
 Install a target monitor on your target system and download your
program using the built-in monitor interface of the µVision Debugger.
 Use the Advanced GDI interface to attach and use the µVision
Debugger front end with your target system.
RTOS Kernel
The RTOS Kernel, describes the advantages of using a real-time kernel like the Keil
RTX51 Tiny in embedded systems.
Creation of HEX File
Some applications require a HEX file to download the application software into the
physical device using a Flash programming utility. µVision creates HEX files with
each build process when Create HEX File is enabled in the dialog Options for Target
Output.
If code banking is used, then the application has to be converted with the OC51
Banked Object File Converter prior to using the OH51 Object/Hex converter.

7
When the extended LX51 Linker is used, it is mandatory to use the OHx51 Extended
Object-HEX Converter to generate an Intel HEX-386 file that contains the common
area and all the code banks.
Start Debugging
µVision provides several ways to invoke debugging commands:
 Commands used from the menu Debug or the Debug Toolbar.
 Commands entered manually in the Command Window.
 Commands available from the Context Menu of the Editor or Disassembly
window.
 Debug Functions executed from an initialization file.
Start the Debugger
 Use the Start/Stop Debug Session button from the Debug Toolbar to start
or stop a debugging session.
 The current instruction or high-level statement (the one about to execute) is
marked with a yellow arrow. For each step-command, the arrow moves to
reflect the new current line or instruction.
 Depending on the Options for Target — Debug configuration, µVision loads
the application program and runs the startup code (Run to main ()).
 µVision saves the editor screen layout and restores the screen layout of the
last debug session. When program execution stops, µVision opens an Editor
window with the source text or shows MCU instructions in the Disassembly
Window.
Execute Commands
 Run the program to the next break point, or type GO in the Command Line.
 Halt the program, or press Esc while in the Command Line
 Click Reset from the Debug Toolbar or from the Debug — Reset CPU
Menu or type RESET in the Command Line to reset the CPU.

8
Single-Stepping Commands
 To step through the program and into function calls. Alternatively, you can
enter TSTEP in the Command Line, or press F11.
 To step over the program and over function calls. Alternatively, you can enter
PSTEP in the Command Line, or press F10.
 To step out of the current function. Alternatively, you can enter OSTEP in
the Command Line, or press Ctrl+F11.
On-Chip Peripherals
There are a number of techniques you must know to create programs that can use
the various on-chip peripherals and features of the 8051 family. Use the code
examples provided here to get started working with the 8051.
There is no single standard set of on-chip peripherals for the 8051 family. Instead,
8051 chip vendors use a wide variety of on-chip peripherals to distinguish their parts
from each other. The code examples demonstrate how to use the peripherals of a
particular chip or family. Be aware that there are more configuration options
available than are presented in this text.
Follow the links to the on-chip peripherals:
 Header Files - use the include files to define peripheral registers of the device
in use.
 Startup Code - initializes the microcontroller and transfers control to the
main function.
 Special Function Registers - explains how to use Special Function Registers
(SFRs).
 Register Banks - explains how to use Register Banks.
 Interrupt Service Routines - lists the different interrupt variants on 8051
devices.
 Interrupt Enable Registers - shows how to enable the interrupts.
 Parallel Port I/O - explains how to use standard I/O ports.
 Timers/Counters - explains standard timers and counters.
 Serial Interface - explains the implementation of serial UART
communication.

9
 Watchdog Timer - use a watchdog timer to recover from hardware or
software failures.
 D/A Converter - convert a digital output voltage to an analog output value.
 A/D Converter - convert an analog input voltage to a digital value.
 Power Reduction Modes - put the device into IDLE or POWER DOWN
mode.
Startup Code
Startup Code is executed immediately upon RESET of the target system and
performs the following operations:
 Depending on the device variant, device specific features are configured.
 Clears data memory (optionally).
 Initializes the reentrant stack and re-entrant stack pointer (optionally).
 Initializes the 8051 hardware stack pointer.
 Transfers control to the variable initialization code or to the main C function.

10
Differences Between µVision and C
A number of differences exist between ANSI C and the language subset
to support features in user- and signal functions.
µVision does not differentiate between uppercase and lowercase.
The names of objects and control statements may be written in either
uppercase or lowercase.
µVision has no preprocessor. Preprocessor directives like #define,
#include, and #ifdef are not supported.
µVision does not support global declarations. Scalar variables must
be declared within a function definition. You may define symbols with
the DEFINE command and use them like you would use a global variable.
in µVision, variables may not be initialized when they are declared.
Explicit assignment statements must be used to initialize variables.
µVision functions only support scalar variable types. Structures,
arrays, and pointers are not allowed. This applies to the function return
type as well as the function parameters.
µVision functions may only return scalar variable types. Pointers
and structures may not be returned.
µVision functions cannot be called recursively. During function
execution, µVision recognizes recursive calls and aborts function
execution if one is detected.
µVision functions may only be invoked directly using the function
name. Indirect function calls via pointers are not supported.
µVision supports only the ANSI style for function declarations with
a parameter list. The old K&R format is not supported. For example, the
following ANSI style function is acceptable.

11
High Level Language –‘C’ V/s Embedded C
‘C’ is a well-structured, well defined and standardized general purpose
programming language with extensive bit manipulation support.
‘C’ offers a combination of the features of high level language and assembly
and help sinhard ware access programming (system
level programming ) as well as business package developments (Application
developments like payroll systems, banking applications etc).
The conventional ‘C’ language follows ANSI standard and it incorporates
various library files for different operating systems.
A platform (Operating System) specific application, known as, compiler is
used for the conversion of programs written in ‘C’ to the target processor (on which
the OS is running) specific binary files.
Embedded C can be considered as a subset of conventional ‘C’ language.
Embedded C supports all ‘C’ instructions and incorporates a few target
processor specific functions /instructions.
The standard ANSI ‘C’ library implementation is always tailored to the target
processor /controller library files in Embedded C.
The implementation of target processor /controller specific functions
/instructions depends upon the processor /controller as well as the supported cross-
compiler for the particular Embedded C language.
A software program called ‘Cross-compiler’ is used for the conversion of
programs written in Embedded C to target processor /controller specific instructions.

12
Procedure:-
Create new u vision project
Select the folder (newly created) to save the project

13
Save the project
Select the vendor “Atmel” and device “AT89C51”

14
Addition of STARTUP.A51 to project folder
STARTUP.A51 is added

15
The program to print “welcome to ECE department” is written
The program is saved as prg3.c

16
Prg3.c is to be added to Source Group1
Select the program prg3

17
Now prg3.c is added to Source Group 1
Build the target

18
Debugging the target
New window evaluation mode appeared. Press ok

19
Run the program
Selecting for UART#1 from serial windows

20
Check the output at UART#1 window
Select Port1 from i/o ports in peripherals

21
Port1 window is displayed with D0 as 0

22
Stop debugging process
After debugging, window appears in this format

23
Experiment-2
Aim of the Experiment: - Write a C Program to print hello world.
Software required: - Keil u vision 5
Theory: - This experiment aims to print “hello world” using the software keil u
vision 5. The program is by default present after installation of this software. Firstly
the header files REG52.H, stdio.h are declared for the intended 8051. Programming
for debugging with Monitor-51is made. Now the main function starts. The serial port
for 1200 baud at 16MHz is set up. An embedded program never exits (because there
is no operating system to return to). It must loop and execute forever. So an infinite
loop is made that Toggle P1.0 each time we print "Hello World".
Program:-
#include <REG52.H>
#include <stdio.h>
#ifdef MONITOR51
char code reserve [3] _at_ 0x23;
#endif
void main (void)
{
#ifndef MONITOR51
SCON = 0x50;
TMOD |= 0x20;
TH1 = 221;
TR1 = 1;
TI = 1;
#endif
While (1) {
P1 ^= 0x01;
printf ("Hello Worldn");
}
}

24
Procedure:-
As said the program for hello world is by default present after the installation of the
keil u vision software, the program is loaded by following certain steps which is as
follows:-
Select open project from project

25
Select Keil_v5 present in Local Disk (C:)
Next select the folder C51

26
Next select the folder examples
Next select the folder HELLO

27
Now select and open uvision4 project file
After selecting the window appears in this format (HELLO.C is added to Source
Group 1)

28
Program of HELLO.C
Build the target

29
Displaying 0 errors and 0 warnings
Debugging the target

30
Now the window appears in this format

31
Run the program
Selecting for UART#1 from serial windows

32
Check the output at UART#1 window
Select Port1 from i/o ports in peripherals

33

34
Then stop debugging the process
After closing the program, the window appears in this format

35
Now remove HELLO.C from source group 1
Now select yes

36
Output:-
HELLO WORLD with D0=1
HELLO WORLD with D0=0

37
Observation:-
From the above outputs it is analyzed that the message “hello world” is printed at
UART#1 at each time P1.0 is toggled.
Conclusion:-
The experiment to print hello world using keil u vision successfully.

38
Experiment-3
Aim of the experiment:- Write a C program to store the data in the accumulator.
Theory: - This experiment aims to store any data in the Accumulator using the
software keil u vision 5. In this program, the data 0x05 is to be stored in accumulator
i.e. value 05 in hexadecimal. Firstly the header files REG51.H is declared for the
intended 8051. Then the main function starts. In the main function 0x05 is stored in
Acc variable.
Program:-
#include<reg51.h>
void main()
{
Acc=0x05;
}
Procedure :- The procedure for the program of storing a data in accumulator is as
follows.
A new file is is created

39
The program is written
The program is to be saved

40
The program is saved in a new folder (created folder ece lab)
The program is to be saved with the extension .c

41
Addition of prg1.c to the Source Group1
The newly created folder ece lab is selected

42
Now prg1.c is selected
Check whether the prg1.c is added in Source Group1 or not. Now bulid(F7) the
target.

43
Check for any errors in program in the build output. Here displaying 0 errors and 0
warnings.
Start debugging session

44

45
Run the program
Select step from debug or press F11

46
Check the value of a register.
Output:-
The value of accumulator is 05
Observation:-
From the above output it is analyzed that the value 05 is stored in accumulator.
Conclusion:-
The experiment to store any data in accumulator using keil u vision successfully.

47
Experiment-4
Aim of the experiment:- Write a C Program to send values 00-ff to Port 1.
Theory: - This experiment aims to send value 00-ff using the software keil u vision
5. In this program, the data 00-ff is to be sent to Port1. Firstly the header files reg51.H
is declared for the intended 8051. Then the main function starts. In the main function
an unsigned character is initialized followed by a for loop where 0-255(00-ff) is
assigned to Port1.
Program:-
#include<reg51.h>
void main()
{
unsigned char z;
for(z=0; z<=255; z++)
P1=z;
}
Procedure: - The procedure for the program of storing a data in accumulator is as
follows.
FilenewProgram(code) Save  Add existing files to source group 1
Build Start Debug Run  Peripherals Port1 Debug the process

48
Output:-
Observation:-
From the above output it is observed that the data 00-ff is sent to Port1.
Conclusion:-
The experiment to send values 00-ff to Port 1 using keil u vision successfully

49
Experiment-5
Aim of experiment:- Write a C Program to send hex values for ASCII characters
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f to port 1
Software required:- Keil u vision 5
Theory :- This experiment aims to send hex values for ASCII characters 0, 1, 2, 3,
4, 5, 6, 7, 8, 9, a, b, c, d, e, f to port 1 using the software keil u vision 5. Firstly the
header files reg51.H is declared for the intended 8051. Then the main function starts.
In the main function an unsigned character array is initialized
with”0123456789abcdef” and then unsigned character variable is initialized
followed by a for loop. The loop runs for 16 time where each time one character
from array is sent to Port1.
Program:-
#include<reg51.h>
void main()
{
unsigned char a[] = "0123456789abcdef";
unsigned char z;
for(z=0; z<=16; z++)
P1=a[z];
}
Procedure:- The procedure for the program of storing a data in accumulator is as
follows.
Build Start Debug Run  Peripherals Port1 Insert Break Point at
P1Debug the process

50
Output:-
1. For input ‘0’ 2. For input ‘a’
Observation:- From the above output it is observed that the data 0, 1, 2, 3, 4, 5,
6, 7, 8, 9, a, b, c, d, e, f is sent to Port1.
Conclusion:- The experiment to send values 00-ff to Port 1 using keil u vision
successfully.

51
Experiment-6
Aim of experiment:- Write a C program to toggle all the bits of P1 continuously.
Software required:- Keil u vision
Theory:- This experiment aims to toggle all the bits of Port1 continuously using
the software keil u vision 5. Firstly the header files reg51.H is declared for the
intended 8051. Then the main function starts. In the main function an infinite for
loop starts where each time 0x55 followed by 0xAA is sent to Port1 and the loop
goes on.
Program:-
#include <reg51.h>
void main()
{
for (;;)
{
p1=0x55;
p1=0xAA;
}
}
follows.
Build Start Debug Run  Peripherals Port1 Debug (step) Debug the
process

52
Output:-
Observation:- From the above output it is observed that all the bits of P1 are
toggling continuously.
Conclusion:- The experiment to toggle all the bits of P1 continuously using keil
u vision successfully

53
Experiment-7
Aim of experiment:- Write a C program to toggle bit D0 of port 1 50,000 times.
Software required:- keil u vision
Theory:- This experiment aims to toggle bit D0 of Port1 50,000 times using the
software keil u vision 5. Firstly the header files reg51.H is declared for the intended
8051. The sbit keyword is a widely used 8051 C data type designed specifically to
access single bits of SFR registers. Here we use sbit toaccess the individual bits of
the Port1. Then the main function starts. In the main function a for loop runs 50000
times where each time D0 of Port1 is made 0 and then 1.
Program:-
#include <reg51.h>
sbit MYBIT=P1^0;
void main(void)
{
unsigned int z;
for (z=0;z<=50000;z++)
{
MYBIT=0;
MYBIT=1;
}
}
follows.
Build Start Debug Run  Peripherals Port1 Debug (step) Debug the
process

54
Output:-
Observation:- From the above output it is observed that the bit D0 of the Port1
(P1.0) is toggled 50,000 times.
Conclusion:- The experiment to toggle bit D0 of port 1 50,000 times using keil u
vision successfully

55
Experiment-8
Aim of experiment:- Write a C program to generate a square wave for 1ms delay.
Theory:- This experiment aims to generate a square wave for 1ms delay using
the software keil u vision 5. There are two ways to create a time delay in 8051 C: 1.
Using a simple for loop 2. Using the 8051 timers.
Program:-
#include<reg51.h>
void delay( void );
void main()
{
for(;;)
{
P1=0x00;
delay();
P1=0xFF;
delay();
}
}
void delay(void)
{
TMOD=0x01;
TL0=0X18;
TH0=0XFC;
TR0=1;
while(TF0==0);

56
TR0=0;
TF0=0;
}
follows.
Build Start Debug Run  Analysis Window Set up New Write P1
Close  Run Debug the process
Output:-

57
Observation:-
From the above output it is observed that the square wave is generated in the analysis
window.
Conclusion:-
The experiment to to generate a square wave for 1ms delay using keil u vision is
done successfully

58
Experiment-9
Aim of experiment :- Write a C program to send the data serially.
Theory:- This experiment aims to send the data serially using the software keil u
vision 5.
Program:-
#include<reg51.h>
void main()
{
TMOD=0X20;
TH1=0XFA;
SCON=0X50;
TR1=1;
while(1)
{
SBUF='A';
while(TI==0)
TI=0;
}
}
Procedure:- Program(code) Save  Add existing files to source group 1
Build Start Debug Run  View Serial WindowUART#1Check the
output Debug the process

59
Output:-
Observation:-
From the above output it is observed that the data is sent serially .
Conclusion:-
The experiment to to generate a square wave for 1ms delay using keil u vision is
done successfully

60
Experiment-10
Aim of experiment:- Write a C program to receive the data serially
Theory:- This experiment aims to receive the data serially using the software keil
u vision 5.
Program:-
#include<reg51.h>
void main()
{
unsigned char mydata;
TMOD=0x20;
TH1=0xFA;
SCON=0X50;
TR1=1;
while(1)
{
while(RI==0);
mydata=SBUF;
P1=mydata;
RI=0;
}
}
Procedure:- FilenewProgram(code) Save  Add existing files to source
group 1 Build Start Debug Run  View Serial
WindowUART#1Check the output Debug the process

61
Output:-
FOR 8 INPUT
FOR 9 INPUT

62
Observation:-
From the above output it is observed that the data as input 8 (in ASCII as 38) and
input 9 (in ASCII as 39) is received serially
Conclusion:-
The experiment to receive the data serially using Keil u vision is done successfully

63
Experiment-11
Aim of the experiment:- Write a C program to convert packed BCD 0x29 to
ASCII and Display the bytes on P1and P2.
Theory:- This experiment aims to convert packed BCD 0x29 to ASCII. To covert
packed BCD to ASCII, it must be converted to unpacked BCD is tagged with
00110000(30H).
Packed BCD Unpacked BCD ASCII
0x29 0x02,0x09 0x32,0x39
00101001 00000010, 00001001 00110010,00111001
Program:-
#include <reg51.h>
void main(void)
{
unsigned char x,y,z;
unsigned char mybyte=0x29;
x=mybyte&0x0F;
P1=x|0x30;
y=mybyte&0xF0;
y=y>>4;
P2=y|0x30;
}
Procedure:- Filenew Program(code) Save  Add existing files to source
group 1 Build Start Debug Run  Peripherals Port1 Peripherals
Port2 Stop debug the process

64
Output:-
Observation:-
From the above output it is observed that packed BCD 0x29 is converted to ASCII
and Port2 displays 0x32 (00110010) and Port1 displays 0x39 (00111001) .
Conclusion:-
The experiment to convert packed BCD 0x29 to ASCII using keil u vision
successfully.

65
Experiment-12
Aim of the experiment:- Write a C program to convert the hex to decimal and
display the digits on P0, P1, and P2.
Theory:- One of the most widely used conversions is the binary to decimal
coversion.in devices such as ADC(Analog to Digital Conversion) chips, the data is
provided to the microcontroller in binary. In order to display binary data we need to
convert it to decimal and then to ASCII. Since the hexadecimal format is a
convenient way of representing binary data we refer to the binary data as hex. This
experiment aims to to convert the hex to decimal using the software keil u vision 5.
Firstly the header files reg51.H is declared for the intended 8051. Then the main
function starts. One way to do this is to divide it by 10 and keep the remainder.
Program:-
#include <reg51.h>
void main(void)
{
unsigned char x,binbyte,d1,d2,d3;
binbyte=0xFD;
x=binbyte/10;
d1=binbyte%10;
d2=x%10;
d3=x/10;
P0=d1;
P1=d2;
P2=d3;
}
Procedure:- Filenew Program(code) Save  Add existing files to source
group 1 Build Start Debug Run Peripherals Port0 Peripherals
Port1 Peripherals Port2Debug the process

66
Output:-
Observation:-
From the above output it is observed that the binary data 00-ff H is converted to
decimal which will give us 000-255. In this program binary data 11111101 or FD H
is converted to decimal 253 and the output is checked at Port0, Port1 and Port2.
Conclusion:-
The experiment to convert the hex to decimal and displaying the digits on P0, P1,
and P2 using keil u vision successfully.

Embedded c lab and keil c manual

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