The 8085 Microprocessor

Table :- Intel Microprocessors Historical perspective The first Microprocessor (4004) was designed by Intel Corporation which was founded by Moore and Noyce in 1968. In the early years, Intel focused on developing semiconductor memories (DRAMs and EPROMs) for digital computers. In 1969, a Japanese Calculator manufacturer, Busicom approached Intel with a design for a small calculator which need 12 custom chips. Ted Hoff, an Intel Engineer thought that a general purpose logic device could replace the multiple components. This idea led to the development of the first so called microprocessor. So, Microprocessors started with a modest beginning of drivers for calculators. With developments in integration technology Intel was able to integrate the additional chips like 8224 clock generator and the 8228 system controller along with 8080 microprocessor with in a single chip and released the 8 bit microprocessor 8085 in the year 1976. The 8085 microprocessor consiste

To assemble a program automatically the assembler needs information in the form of assembler directives that controls the assembly or Assembler directives are the directions to the assembler which indicate how an operand or section of the program is to be processed. These are also called pseudo operations which are not executable by the microprocessor. For example, the assembler must be told at what address to start assembling the program. These assembler directives are command placed in the program by the designer that provides information to the assembler. They do not become part of the final program as they are not the part of the instruction set of the microprocessor nor did they translate into executable code. Therefore, they are also known as pseudo-instruction on false instructions. Each assembler has its own unique pseudo instructions or assembler directives. These instructions differ from assembler to assembler but most of the assembler contains an equivalent set of pseu

ASSEMBLY LANGUAGE PROGRAMMING EXAMPLES Addition Programs Example 1 : Addition of two 8-bit numbers whose sum is 8-bits. Explanation: This assembly language program adds two 8-bit numbers stored in two memory locations .The sum of the two numbers is 8-bits only. The necessary algorithm and flow charts are given below. ALGORITHM: Step1. : Initialize H-L pair with memory address XX00 (say: 9000). Step2. : Clear accumulator. Step3. : Add contents of memory location M to accumulator. Step4. : Increment memory pointer (i.e. XX01). Step5. : Add the contents of memory indicated by memory pointer to accumulator. Step6. : Store the contents of accumulator in 9002. Step7. : Halt PROGRAM: Address of the memory location Hex code Label Mnemonics Comments Op-code Operand 8000 21,00,90 LXI H, 9000 Initialise memory pointer to point the first data location 9000. 8003 3E MVI