This document provides an overview of programming the 8051 microcontroller in C. It discusses machine language, assembly language, and high-level languages. It then demonstrates how to create a hex file using a compiler, burn it to a microcontroller, and use ISP and a universal programmer. Several examples of 8051 C code are provided, including toggling port bits, using data types like unsigned char, delay loops, and reading/writing port values.

2. Outline
 Types of programming languages
 Machine language
 Assembly language
 High level language
 Programming 8051 in C
 Creating hex file using Keil Compiler
 Burning hex file into microcontroller
 ISP
 Universal Super-pro programmer

3. Why program the 8051 in C?
 It is easier and less time consuming 2 write in C than
assembly
 C is easier 2 modify & update
 C code is portable

4. Toggle all the bits of P1 continuously
#include<reg51.h>
void main (void)
{
for(; ;) // repeat forever
{
P1=0x55; // 0x indicates data is in hex
P1=0xAA;
}
}

5. C data types for the 8051
 Since one of the goals of 8051 C programmers is to
create smaller hex files, it is worthwhile to re-examine
C data types for 8051 C
 This will help programmers 2 create smaller hex files

6. Unsigned char
 8-bit data type-takes value in the range of 0-255 (00-
FFH)
 Most widely data types for the 8051
 Signed char is default

7. Write an 8051 C program to send values 00-FF to
P1
#include<reg51.h>
Void main (void)
{
unsigned char z;
for(z=0;z<=255;z++)
P1=z;
}

8. Signed char
 8-bit data type dat uses d MBS-D7 to represent – or +
value
 Values from -128 to +127
 Default is signed char

9. Unsigned int
 16-bit data type
 Values in the range 0-65535 (0000-FFFF H)
 Used to set counter values of >256
 Takes 2 bytes of memory

10. Sbit data type
Used for a single bit
Format:
sbit name= bit
For ex:
sbit LED =P1^0

11. Write an 8051 C program to toggle bit D0 of port
P1 50,000 times
#include<reg51.h>
sbit MYBIT=P1^0; //sbit is declared out of main
//program
Void main (void)
{
unsigned int z;
for(z=0;z<50000;z++)
{
MYBIT=o;
MYBIT=1;
}
}

12. Time delay using C
 There are two ways to create a time delay in 8051 C:
1. Using a simple for loop
2. Using the 8051 timers

13. Three factors that can affect the accuracy of delay
 Compiler choice
 Crystal frequency
 The 8051 design
 Original 8051 design used 12 clock periods per m/c cycle
 DS5000- 4 clock periods per m/c cycle
 DS89C420- 1 clock periods per m/c cycle

14. Toggle all the bits of P1 continuously with some
delay
#include<reg51.h>
void main (void)
{
unsigned int x;
for(; ;) // repeat forever
{
P1=0x55; // 0x indicates data is in hex
for (x=0;x<40,000;x++); //delay size unknown
P1=0xAA;
for (x=0;x<40,000;x++);
}
}

15. Get a byte of data from P0. If it is less than 100,
send it to P1; otherwise send it to P2
#include<reg51.h>
void main (void)
{
unsigned int mybyte;
P0=0xFF;
for(; ;) // repeat forever
{
mybyte = P0; // 0x indicates data is in hex
if(mybyte<100)
P1=mybyte; //send it to P1 if less than 100
else
P2=mybyte; //send it to P2 if more than 100
}
}