8051 programming in c

8051 programming in c

• 2.
  Outline  Types ofprogramming 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 the8051 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 thebits 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 typesfor 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-bitdata 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 8051C 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-bitdata type dat uses d MBS-D7 to represent – or + value  Values from -128 to +127  Default is signed char
• 9.
  Unsigned int  16-bitdata 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 Usedfor a single bit Format: sbit name= bit For ex: sbit LED =P1^0
• 11.
  Write an 8051C 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 usingC  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 thatcan 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 thebits 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 byteof 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 } }