8051 programming in c
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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.
8051 programming in c
- 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 } }