5 th sem electrical GUIDED BY: Prof. KETAN PATEL 1

The main concern in mocrocontroller programming is program memory space. Assembly languge prpgramming produced a hex file that is much smaller than that poduced y pprogramming Iin c But pograming in c has fllowing advantages over assembly. 1.programming in C less tedious and less time consuming as compared to assembly. 2. it is easier to modify and update. 3 it is ortableto other mirocontrollers with little modification. 4.C also provide some library funcaton. Keil vision has a Header file microcontroller. This header file contains variable delaraon,macro definition for special function registers(SFRs).The header file for 8051 is reg 51h.thos file given namses for all the SFRs and hence become convention fr the programmer to write the program to directly by using these names. The main even to the SFRs are as used by us in normal programming such as P0 for PORT OR port1,TCON for control register etc.

Data typeSize in bitsRange of usage Unsigned char 80 to 255(00H to FFH) (signed char) to +127 Unsigned into 16 0 to 65535(0000H to FFFFH) (signed)int to S bit 1 Bit addressable location of SFRs Bit 1 Bit addressable location of internal RAM SFR 8SFR location of 8051 i.e. 80H to FFH(only used location) Data Type in 8051

#include void main () { unsigned char a; for (a=0; a<=255;a++) { P2=a; //assign variable a to P2 pins } Program1: Write an embedded C program for 8051 to count 00H to FFHon port P2

Program2: write on 8051 C program to send hex values for ASCII characteres of A B C X Y and Z to port P1. Program: #include void main (void) { unsigned char mydisp[]="012345ABCXYZ"; unsigned char i; For (i=0;i<12;i++) P1=my disp[i]; }

Program3: Write 8051 C program to toggle MSB bit of port1. PROGRAM: #include sbit mybit=P1^7; //P1^7 represents MSB bit of port 1 void main(void) { unsigned into i; for (i=0;i<=10000;i++) { mybit=0; mybit=1; }

 Control statments and loops in Embedded C Control loops The control loops are used for specify the manner in which the computation in a program are to below. the Different type programming are: 1.IF 2.IF ELESE 3.FOR-LOOP 4.WHILE 5.SWITCH 1.IF statement IF the condition is true the statement following the if statement is executed otherwise,it skipped. It has format: If condition Statement; If(mybit==1) P1=0xFFH //if mybit=1 then data on p1=FFH

2.if…else statement The if..Else statement is a conditional statement. IF the condition is true the statement following the if statement executed, otherwise the statement following else is executed.  Statement; if(mybit==1) p1=oxFF; else p1=0x00 //if mybit=1 then the data on p1=FFH otherwise p1=00h. 3.for-loop statement The for loop statement is conditional statement. its format is : for (expression1;expression2;expression3)  Statement; where,expression1 and expression3 are function calls and expression 2 is a relative expression. e.g. the following for loop turn on LED 100 times: (i=0;i<100;i++) { LED=1; }

4.While statement While statement is true,the while loop repeats the a statement or block of code.  Program #include sbit mybit=p1^4; unsigned char x; Void main() { while(1) { mybit=0; for(x=0;x<=5000;x++) mybit=1; for(x=0;x<=5000;x++) }

 Programming for time delay There are two ways to create a time delay in 8051 C: 1.Using a simple for loop 2.Using the 8051 timers In either case, when we write a time delay we must use the oscilloscope to measure the duration of our time delay. Next, we use the for loop to create time delays. Discussion of the use of the 8051 timer to create time delays is postponed until Chapter 9. In creating a time delay using a for loop, we must be mindful of three factors that can affect the accuracy of the delay. 1.The 8051 design. Since the original 8051 was designed in 1980, both the fields of 1C technology and microprocessor architectural design have seen great advancements. As we saw in Chapter 3, the number of machine cycles and the number of clock periods per machine cycle vary among different versions of the 8051/52 microcontroller. While the original 8051/52 design used 12 clock periods per machine cycle, many of the newer generations of the 8051 use fewer clocks per machine cycle. For example, the DS5000 uses 4 clock peri ods per machine cycle, while the DS89C420 uses only one clock per machine cycle. 2.The crystal frequency connected to the XI – X2 input pins. The duration of the clock period for the machine cycle is a function of this crystal frequency. 3.Compiler choice. The third factor that affects the time delay is the compiler used to compile the C program. When we program in Assembly language, we can control the exact instructions and their sequences used in the delay sub routine. In the case of C programs, it is the C compiler that converts the C statements and functions to Assembly language instructions

program5.: write an embedded program for 8051 to toggle the bits of p1 continuously using software delay. program: #include void main() { into; while (1) { P1=0x00; for(x=0;x<=5000;x++) P1=0xFF; for(x=0;x<=5000;x++)

 I/O Programming in 8051C bytes Size I/O The port P0-P3 are byte accessible.we use labels P0-P3 as defined in 8051/5c header file. Programe6: write an 8051 c program to get a byte of data p1 wait for ½ second and then send it to P2.use crystal frequency of mHz. Program: #include <reeg51.h. void main (void) { P1=0xFF; unsigned char x; while (1) { x=P1; delay(500); } void delay(unsigned into time) { unsigned into i; for(i=0;<itime;i++) for(j=0;j<1275;j++) }

 Bit Addressable I/O Programming the port p0-P3 are bit addressable.we can access a single bit without disturbing the other port bits. A way of doing it is using Pi^j where I is port 0,1,2or3 and j is the bit 0-7 of that port. Program8: write an embedded C program for 8051 to continuously toggle port 1 pin4 without disturbing other pins of port 1 using software delay. program: #include sbit mybit=P1^4; unsigned char x; void main () { while(1) { mybit=0; for (x=0;x,=5000;x++) mybit=1 for(x=0;x<=5000;x++) }

 Using bit type data for bit Addressable RAM. we can use 8bit data type with only bit addressable SFR registers. To access addressable section of data RAM space 20-2FH,. Program 10:Write an 8051 C program to get the status of port 2.7 pin and send it to port 2.0 pin continuously. Program: #include sbit in =P2^7; sbit out=P2^0; void main () { while(1) { out in; }

 Logic operations in 8051C ABAND A&B OR A/B EX-OR A^B INVERTER Y=-B 0O O

PROGRAME10:Write an 8051 C program to toggle all pins of port 0,1,2,and3 continuously with a software delay. Use Ex-or Operator. Program: Sfrp0=0x80; sfrP1=0x90; sfrP2=oxA0; sfrP3=0xB0; Unsigned char I; Void main () { while(1) { P0=0x00; P1=0x00; P2=0x00; P3=0x00; for9i=0;i<100;i++) P0=P0^0xFF; P1=P1^0xFF; P2=P2^0xFF; P3=P3^0xFF; }

 DATA Serializations using 8051 C There are two method to implement this 1.Serial port 2. serialization: In serialization we use shift instruction and transfer the bit one bit. programe12:write a C program to send out the value 56h serially at a time via P3.0.the LSB should go out first. Program: #include Ssbit out=P3^0; Sbit serial=ACC^0; Void main () { unsigned char dat=0x56; signed char I; for (i=0;<8;i++) { ACC=dat; out=serial; ACC=ACC>>1; } while(1) }

Program 13:Write C program to bring in a byte of data serially one bit at a time via P3.0.this LSB should come in first. Program #include Sbit serial=ACC^7; Sbit in=P3^0; Void main () { unsigned char dat 0,I; for 9i=0;i,<7;i++) { ACC=dat; serial=in; dat=ACC; dat=dat>>1; }

 Serial Port Programming in C The SFR register 8051 are directly accessible in 8051 C by adding reg 51.h file. To use second serial port we have to decalre the byte address of new SFR register. Programe14:write an 8051 C program to transfer WELCOME serially at 9600 baud rate do this continuously. Program: #include Unsigned char a[]=“welcome” Void main() { TMOD=0x20; TH1=0xFD; SCON=)x50; TR1=1; while(1) { for(i=0,i<=15;i++) { SBUF=a[i]; while(T1) T1=0 }

Program15: program the 8051 in c to receive the data serially and put them in P1.set the baud rat at 4800,8bit data and 1stop bit. Program: #include Void main (void0 { TMOD=0x20; TH1=0xFA; SCON=0x50; TRI=1; WHILE(1) { while(RI!=1); P1=SSBUF RI=0; }

6/13/2016APPLICATIONS OF OP AMP21