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Microprocessor Articles
Page 22 of 42
BCD numbers in 8085 Microprocessor
Many a time, we are required to represent decimal numbers in a computer, and perform arithmetic on these numbers. For example, we may be required to total the marks a student has obtained in five different subjects, where obviously, the marks are awarded in decimal notation.For this purpose, the BCD code is extensively used. In BCD notation, 4 bits are used to code a digit, and so two digits of information are stored in a Byte. For example, decimal 45 is represented in BCD as of 0100 0101. Codes 10 to 15 i.e. 1010, 1011, 1100, 1101, 1110, and 1111 ...
Read More8085 Program to Subtract two multi-Byte numbers
Now let us see a program of Intel 8085 Microprocessor. This program is mainly for subtracting multi Byte numbers.Problem Statement:Write 8085 Assembly language program to add two multi-Byte numbers.Discussion:We are using 3-Byte numbers. The numbers are stored into the memory at location 8001H and 8004H. One additional information is stored at location 8000H. In this place we are storing the Byte count. The result is stored at location 8050H.We are taking the address of first operand block address into DE register pair, and the second operand block address into HL pair. The BC register pair is storing the destination address ...
Read MoreGeneration of time delay in 8085
In this section we will see how to generate the time delay using 8085 programs. The delay will be used in different places to simulate clocks, or counters or some other area.When the delay subroutine is executed, the microprocessor does not execute other tasks. For the delay we are using the instruction execution times. executing some instructions in a loop, the delay is generated. There are some methods of generating delays. These methods are as follows.Using NOP instructionsUsing 8-bit register as counterUsing 16-bit register pair as counter.Using NOT instructions:One of the main usage of NOP instruction is in delay generation. ...
Read MoreProgram counter (PC) in 8085 Microprocessor
PC is a 16-bit register. It contains a memory address. PC contains that very memory address from where the next instruction is to be fetched for execution. Suppose the PC contents are 8000H, then it means that the 8085 Desires to fetch the instruction Byte at 8000H. After fetching the Byte at 8000H, the PC is automatically incremented by 1. This way 8085 becomes ready to fetch the next Byte of the instruction (in case instruction fetch is incomplete), or fetch the next opcode (in case instruction fetch is over).So in this example, first of all PC is loaded with ...
Read More8085 Program to simulate decimal down counter
Now let us see a program of Intel 8085 Microprocessor. In this program we will see how to simulate the decimal down counter.Problem Statement:Write 8085 Assembly language program to simulate decimal down counter.Discussion:In this section we are simulating the decimal down counter. Here the counter will count 100 decimal numbers from 99 to 0. All values will be updated in each 0.5 seconds. For decimal count we are using the DAA instruction.Note: Here for simplicity we are storing the numbers into memory. To simulate it like a counter we can use 7-segment display to show the numbersInput:Here we are not ...
Read MoreInstruction register (IR) in 8085 Microprocessor
IR (Instruction Register) is a special purpose register, which is used to receive the 8-bit opcode portion of an instruction. It is not accessible to the programmer. What it means is that there are no instructions by which the programmer can load it with values of his choice. For example, instructions like ‘MOV IR, D’ or ‘MVI IR, 45H’ are not present in the instruction set of 8085. Thus, IR register is not shown in the programmer's view of 8085.Let us consider one example. First of all, PC is loaded with the value 8000H. This is done by typing the ...
Read More8085 Program to simulate a real-time clock
Now let us see a program of Intel 8085 Microprocessor. In this program we will see how to generate real time clock using 8085.Problem Statement:Write 8085 Assembly language program to simulate real-time clock.Discussion:In this program we are creating a real time clock using 8085MPU. Here we are generating 1s delay to update seconds. This clock is 24Hrs clock. We are initializing the clock from 00:00:00. To display the values into 7-segment display we have to use some Port ICs and correct configurations. In each 60 seconds the minute field is updated, and in each 60 minutes the hour field is ...
Read More8085 Program to convert a 16-bit binary number to BCD
Now let us see a program of Intel 8085 Microprocessor. In this program we will see how to convert 16-bit binary data to BCD data.Problem Statement:Write 8085 Assembly language program to convert 16-bit binary data to BCD data. The binary data is stored at location 8000H and 8001H.Discussion:This problem is solved by implementing 16-bit counter. We are storing the 16-bit number at first, then decreasing the numbers one by one, and increasing the decimal value by adjusting the decimal value. To increase the value, we can use the INR instruction, but INR instruction does not affect the carry flag. So ...
Read More8085 Program to add the contents of N word locations
Now let us see a program of Intel 8085 Microprocessor. In this program we will see how to add the contents of N word locations.Problem Statement:Write 8085 Assembly language program to add N 16-bit numbers stored into memoryDiscussion:The 16-bit numbers are stored into memory location 8001H onwards. The value of N is stored at location 8000H. After addition, the result will be stored at location 8050H onwards.In 8085 we have few number of registers. So we are storing the count into memory, when we need to update it, we will fetch it from memory, update it and then again store ...
Read More8085 Program to multiply two 8-bit numbers (shift and add method)
Now let us see a program of Intel 8085 Microprocessor. In this program we will see how to multiply two numbers using shift and add methods.Problem Statement:Write 8085 Assembly language program to multiply two 8-bit numbers using shift and add method.Discussion:The shift and add method is an efficient process. In this program, we are taking the numbers from memory location 8000H and 8001H. The 16 bit results are storing into location 8050H onwards.In this method we are putting the first number into DE register pair. The actual number is placed at E register, and D is holding 00H. The second ...
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