Introduction to Embedded system programming using 8051
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The document discusses data types and programming in assembly language and C for 8051 microcontrollers. It provides examples of common data types for 8051 like unsigned char, signed char, unsigned int, and more. It also provides examples of assembly language and C code for basic operations like toggling ports and sending values to ports. The document compares assembly language and C, noting advantages of C like easier maintenance and portability between microcontrollers.
![Write an 8051 C program to send hex values for ASCII
characters of 0, 1, 2, 3, 4, 5, A, B, C, and D to port P1.
Solution:
#include <reg51.h>
void main(void)
{
unsigned char
mynum[]={'0','1','2','3','4',’5’6',
'7‘,’8','9','A'};
unsigned char z;
for (z=0;z<=10;z++)
P1=mynum[z];
}](https://image.slidesharecdn.com/programmingusingembeddedcpart1-201017141407/85/Introduction-to-Embedded-system-programming-using-8051-11-320.jpg)
Introduction to Embedded system programming using 8051
- 1. DR. VIKAS J. DONGRE HOD ELECTRONICS & TELECOM GOVERNMENT POLYTECHNIC WASHIM (MS) EMAIL: [email protected] Unsigned char Signed char Unsigned int Signed int Sbit (SFR bit) Bit sfr
- 2. Microcontroller 8051 Assembly language programming Need to know architecture Need to know all SFRs Need to know various registers, register banks Need to know various instructions A B R0 R1 R2 R3 R4 R5 R6 R7
- 5. ORG 0000H START: MOV P2,#0FFH CALL DELAY MOV P2,#00H CALL DELAY SJMP START DELAY: MOV R2,#01H D2: MOV R1,#0E1H D1: MOV R0,#0FFH D0: DJNZ R0,D0 DJNZ R1,D1 DJNZ R2,D2 RET END Microcontroller 8051 Assembly language programming
- 6. The reasons for writing programs in C It is easier and less time consuming to write in C than Assembly C is easier to modify and update C supports I/O You can use code available in function libraries One doesn't need to remember all architecture, registers, instructions of specific microcontroller C code is portable to other microcontroller with little of no modification A good understanding of C data types for 8051 can help programmers to create smaller hex files
- 7. Comparison of Assembly language and Embedded C Assembly program Embedded C program 1. Program executes faster Program executes slower 2. Hard to develop and maintain Easy to develop and maintain 3.Requires less memory Requires huge memory 4.Not portable as machine dependent Portable as machine independent 6. Higher software development cost Less software development cost 7.Less scalable and reliable More scalable and reliable 5. Size of program is less Size of program is largs
- 8. Supported data types in embedded C Unsigned char Signed char Unsigned int Signed int Sbit (single bit) Bit sfr
- 9. Data types and their ranges Data types Size Range bit 1-bit RAM bit-addressable only sbit 1-bit SFR bit-addressable only (signed) int 16-bit -32768 to +32767 unsigned int 16-bit 0 to 65535 (signed) char 8-bit -128 to +127 unsigned char 8-bit 0 to 255 Sfr 8-bit 0 to 255 C compilers use the signed char as the default if we do not put the keyword unsigned
- 10. Write an 8051 C program to send values 00 – FF to port P1. #include <reg51.h> void main(void) { unsigned char z; for (z=0;z<=255;z++) P1=z; } Solution:
- 11. Write an 8051 C program to send hex values for ASCII characters of 0, 1, 2, 3, 4, 5, A, B, C, and D to port P1. Solution: #include <reg51.h> void main(void) { unsigned char mynum[]={'0','1','2','3','4',’5’6', '7‘,’8','9','A'}; unsigned char z; for (z=0;z<=10;z++) P1=mynum[z]; }
- 12. Write an 8051 C program to toggle all the bits of P1 continuously. Solution: //Toggle P1 forever #include <reg51.h> void main(void) { for (;;) { P1=0x55; P1=0xAA; } }
- 13. Write an 8051 C program to toggle bit D0 of the port P1 (P1.0) 50,000 times. Solution: #include <reg51.h> sbit MYBIT=P1^0; void main(void) { unsigned int z; for (z=0;z<=50000;z++) { MYBIT=0; MYBIT=1; } }