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Showing posts from December, 2020

Interrupts in 8085 Microprocessor: Vectored-Non Vectored Interrupts And Maskable-Non Maskable Interrupts

Vectored Interrupt: In vectored interrupts, the manufacturer fixes the address of the ISR to which the program control is to be transferred. the processor automatically branches to the specific address in response to an interrupt.  • The TRAP, RST 7.5, RST 6.5 and RST 5.5 are vectored interrupts. Non-Vectored Interrupt:   But in non-vectored interrupts the interrupted device should give the address of the interrupt service routine (ISR).    • The INTR is a non-vectored interrupt. Hence when a device interrupts through INTR, it has to supply the address of ISR after receiving interrupt acknowledge signal. Maskable & Non-Maskable Interrupt: The hardware vectored interrupts are classified into maskable and non-maskable interrupts.  • TRAP is non-maskable interrupt.  • RST 7.5, RST 6.5 and RST 5.5 are maskable interrupt. Masking is preventing the interrupt from disturbing the main program. When an interrupt is masked the processor will not accept the interrupt signal. The interrupts ca

Interrupts in 8085 Microprocessor-Hardware Interrupt And Software Interrupt

What is Interrupt and how it is generated? Interrupt is a signal send by an external device to the processor, to the processor to perform a particular task or work. In the microprocessor based system the interrupts are used for data transfer between the peripheral and the microprocessor. When a peripheral is ready for data transfer, it interrupts the processor by sending an appropriate signal to the interrupt pin of the processor. If the processor accepts the interrupt then the processor suspends its current activity and executes an interrupt service subroutine to complete the data transfer between the peripheral and processor. After executing the interrupt service routine the processor resumes its current activity. This type of data transfer scheme is called interrupt driven data transfer scheme. Types Of Interrupt: The interrupts are classified into software interrupts and hardware interrupts. • The software interrupts are program instructions. While running a program, if a software

System development And Life Cycle-Implementation and Post Implementation & Maintenance

  Implementation   Stage: User training, File / System conversion Key Question: What is actual operation? Are user manuals ready? Are there delays in loading files? Results: Training programs, user friendly documentation  • It is concerned with user training, site preparation and file conversion. • When system is linked to terminal or remote sites it also includes telecommunication network and network testing along with system. • During final testing user acceptance is tested followed by user training, • System testing checks the readiness and accuracy of system to access, update and retrieve  data from new files. • If testing is successful program is run with live data or else a diagnostic procedure is use to locate and correct errors. Post-Implementation and Maintenance Stage: Evaluation, maintenance and enhancements. Key Questions: is system running? Should system be modified? Results: User requirements need, satisfied user. • There is an aging process require periodic mainten

System development And Life Cycle-Analysis And Design

Analysis Stage: Detailed evaluation of present system data collection. Key Question: What must be done to solve the problem? what are the facts? Result: Logical model of system. Ex: Data flow diagram, data dictionary. • Analysis is a detailed study of various operations performed by a system and their relationships within and outside of the system. • One aspect of it defining the boundaries of system and determining weather or not the system should consider other related system. • Data is collected in available files during analysis. • Interview is commonly used tool in analysis. It requires special skills and sensitivity to the subject. • Training, experience and common sense are required for collecting needed information to do analysis. • After analysis analyst has firm understanding of what is to be done. Design Stage: General design specification, detailed design specification, program construction and testing (output, input, files, procedures) Key Question: In general, how mu

System development And Life Cycle- Recognition of need And Feasibility

  System Development And Life Cycle  An effective System Development Life Cycle (SDLC) should result in a high quality system that meets customer expectations, reaches completion within time and cost evaluations, and works effectively and efficiently in the current and planned Information Technology infrastructure. Recognition of Need  Key Question: What is the problem or opportunity? Stage: Preliminary survey / initial investigation Result: Statement of scope and objectives performance criteria. • Analyst must know what the problem is before it can be solved. • The basic for system development is to recognize of need to improve or develop an information system or a procedure. • This need leads to a preliminary survey or an initial investigation to determine that alternative system can solve the problem. • It includes looking into duplication of effort, bottlenecks, inefficient existing procedures or weather parts of existing system would be candidates for computerization. • If  pro

8085 Microprocessor: De-multiplexing of AD0-AD7 Address and Data Lines

  De-multiplexing of AD0-AD7 of 8085 Microprocessor THE ADDRESS AND DATA BUSES: • 8085 Microprocessor have total 16 address lines and 8 data lines. • 8 signal lines A8 – A15 which are unidirectional. • The other 8 address bits are multiplexed with the 8 data bits. So, the bits AD0 – AD7 are bi-directional and serve as A0 – A7 (address bus) and D0 – D7 (data bus) at the same time. • During the execution of the instruction, these lines carry the address bits during the early part, then during the late parts of the execution, they carry the 8 data bits. In order to separate the address from the data, we can use a latch to save the value before the function of the bits changes. THE CONTROL AND STATUS SIGNALS: • There are 4 main control and status signals. 1. ALE (Address Latch Enable): This signal is a pulse that become 1 when the AD0 –AD7 lines have an address on them. It becomes 0 after that. This signal can be used to enable a latch to save the address bits from the AD lines. 2. RD (Rea

Introduction to System Analysis Design

What is System? System is known as collection of components of a plan. System can be any software, any application or any computer related program. What is Analysis? Analysis is known as research or detail examination on any particular topic by the information or data about that topic given to us. What is Designing? Designing is the process of creating construction of system. It is reference for coding. Properties of System: Organization: It implies structure and order. It is arrangement of components that help to achieve objective. Like as, a computer system is designed around an input device, a central processing unit, an output device and one or more storage units. When linked together they work as a whole system. Interaction: It refers the manner in which each components functions with other components of system. For example, purchasing must interact with production, in computer system CPU must interact with the input device to solve the problem. Interdependence: It means the compo

Farmer's Protest in India-2020

The  Indian farmers' protes t of 2020  is an ongoing protest against the three farm acts  passed by the Indian  Parliament  in 2020.This protest is mainly going on  by farmers of Punjab , Rajasthan and Haryana. Firstly the local protests began in states of Punjab and Haryana.  After two months of protests, farmers from these two states began a movement named ' Dilli Chalo ' , in which tens of thousands of farmers marched towards the national capital. Police and law enforcement used water cannons and tear gas to prevent the farmers from entering Delhi . On 26 November, a nationwide general strike  that reportedly involved approximately 250 million people  took place in support of the farmers. This protest is going on because of three bills which were passed  by the Rajya   Sabha  passed the three bills by 22 September.  The President of India  gave his assent by signing the bills on 28 September, thus converting them into acts. These three acts are: 1.  Farmers’ Produce Trad

Introduction To Microprocessor 8085

  What is Microprocessor? It is an integrated computer circuit that performs all the arithmetic, logical, data transfer and control functions of a CPU. Introduction to 8085 Microprocessor In 1977, Intel Corporation introduced an upgraded version of  microprocessor 8080-the 8085. It was last and most successful 8 bit general purpose microprocessor developed by Intel. The main advantages of 8085 were its internal clock generator, internal system controller, and higher clock frequency. Higher level of component integration reduced 8085's cost and increased it's usefulness. Architecture of 8085 Microprocessor • Components of 8085 Microprocessor 1. Accumulator 2. Temporary Register 3. Registers 4. ALU 5. Flag Registers 6. Instruction Register 7. Instruction Decoder 8. Program Counter 9. Stack  Pointer 10. Timing And Control Unit 11. Serial Input And Output Control 12. Interrupt Unit • Functions of the content of Microprocessor  •        Accumulator: It is a 8-bit register which is