This document discusses input/output (I/O) organization in computer systems. It covers various I/O techniques including programmed I/O, interrupts, direct memory access (DMA), and I/O interfaces. Memory-mapped I/O allows I/O devices to use the same address space as memory. Interrupts allow I/O devices to signal the processor when they need service. DMA controllers can transfer data directly between I/O devices and memory without processor intervention. Buses and interface circuits are used to connect I/O devices to the processor and main memory.
Von-Neumann machine and IAS architectureShishir Aryal
The presentation summarizes the von Neumann machine architecture, the stored program concept, and components of the IAS architecture. It explains that von Neumann introduced the stored program concept where both instructions and data are stored in memory. It then describes the basic components of a von Neumann machine including the CPU, memory, and I/O devices. Finally, it details the specific components of the IAS architecture such as the memory buffer register, accumulator, and instruction register.
The document discusses application I/O interfaces and their characteristics. Application I/O interfaces provide standard ways for operating systems to treat I/O devices uniformly by hiding differences through device drivers. I/O interfaces have characteristics like their data transfer mode (character or block), access method (sequential or random), transfer schedule (synchronous or asynchronous), ability to be shared, speed, and supported input/output directions.
The document discusses the Intel 80486 microprocessor. Some key points:
1) The 80486 is an evolutionary step up from the 80386, integrating the math coprocessor on the chip for faster performance.
2) It has an 8KB internal code and data cache, a floating point unit, and 168 pins in a pin grid array package.
3) The architecture includes address and data buses, cache control signals, and status flags in registers like the 80386. It supports protected mode with virtual memory and multitasking capabilities.
The document discusses the 8051 microcontroller. It begins by describing the key features of the 8051 microcontroller, including that it has an 8-bit CPU, 4KB of internal program memory, 128 bytes of internal data memory, 32 I/O lines that can be used as ports, and two 16-bit timer counters. It then provides more details on the internal architecture, describing the ALU, registers, memory organization, and other components. It concludes by explaining features like the register banks and stack memory.
The document describes the Intel 8259 programmable interrupt controller chip. It contains blocks for buffering data to and from the system data bus, controlling read/write signals, storing interrupt requests in the interrupt request register, masking interrupts in the interrupt mask register, tracking interrupts being serviced in the in-service register, resolving interrupt priorities, and cascading multiple 8259 chips. The pin diagram shows inputs for interrupt requests, read/write control, an ID comparator for cascading, and an 8-bit data bus.
This document provides an overview of microprocessors and microcontrollers. It discusses the evolution of microprocessors from discrete components to integrated circuits. The key components of a microprocessor like the CPU, ALU, and memory are described. Microcontroller fundamentals like PIC microcontrollers and their architecture are also covered. Common applications of microprocessors and microcontrollers are in devices like appliances, automobiles, and industrial control systems. Leading manufacturers of microprocessors and microcontrollers are mentioned.
The document describes how input/output (I/O) devices communicate with the processor and memory. I/O devices are connected to the processor and memory via a shared bus. Each device has a unique address and uses address, data, and control lines on the bus. Interrupts allow I/O devices to signal the processor when they need attention, reducing wasted processor time. Multiple interrupt lines allow different devices to interrupt independently and ensure the correct interrupt service routine is executed.
Von-Neumann machine and IAS architectureShishir Aryal
The presentation summarizes the von Neumann machine architecture, the stored program concept, and components of the IAS architecture. It explains that von Neumann introduced the stored program concept where both instructions and data are stored in memory. It then describes the basic components of a von Neumann machine including the CPU, memory, and I/O devices. Finally, it details the specific components of the IAS architecture such as the memory buffer register, accumulator, and instruction register.
The document discusses application I/O interfaces and their characteristics. Application I/O interfaces provide standard ways for operating systems to treat I/O devices uniformly by hiding differences through device drivers. I/O interfaces have characteristics like their data transfer mode (character or block), access method (sequential or random), transfer schedule (synchronous or asynchronous), ability to be shared, speed, and supported input/output directions.
The document discusses the Intel 80486 microprocessor. Some key points:
1) The 80486 is an evolutionary step up from the 80386, integrating the math coprocessor on the chip for faster performance.
2) It has an 8KB internal code and data cache, a floating point unit, and 168 pins in a pin grid array package.
3) The architecture includes address and data buses, cache control signals, and status flags in registers like the 80386. It supports protected mode with virtual memory and multitasking capabilities.
The document discusses the 8051 microcontroller. It begins by describing the key features of the 8051 microcontroller, including that it has an 8-bit CPU, 4KB of internal program memory, 128 bytes of internal data memory, 32 I/O lines that can be used as ports, and two 16-bit timer counters. It then provides more details on the internal architecture, describing the ALU, registers, memory organization, and other components. It concludes by explaining features like the register banks and stack memory.
The document describes the Intel 8259 programmable interrupt controller chip. It contains blocks for buffering data to and from the system data bus, controlling read/write signals, storing interrupt requests in the interrupt request register, masking interrupts in the interrupt mask register, tracking interrupts being serviced in the in-service register, resolving interrupt priorities, and cascading multiple 8259 chips. The pin diagram shows inputs for interrupt requests, read/write control, an ID comparator for cascading, and an 8-bit data bus.
This document provides an overview of microprocessors and microcontrollers. It discusses the evolution of microprocessors from discrete components to integrated circuits. The key components of a microprocessor like the CPU, ALU, and memory are described. Microcontroller fundamentals like PIC microcontrollers and their architecture are also covered. Common applications of microprocessors and microcontrollers are in devices like appliances, automobiles, and industrial control systems. Leading manufacturers of microprocessors and microcontrollers are mentioned.
The document describes how input/output (I/O) devices communicate with the processor and memory. I/O devices are connected to the processor and memory via a shared bus. Each device has a unique address and uses address, data, and control lines on the bus. Interrupts allow I/O devices to signal the processor when they need attention, reducing wasted processor time. Multiple interrupt lines allow different devices to interrupt independently and ensure the correct interrupt service routine is executed.
The document discusses the bus architecture of the 8085 microprocessor. It covers the bus organization, structure, and key components. The address bus is 16-bits and allows the microprocessor to address up to 65,536 memory locations. The 8-bit data bus is bi-directional and carries data being written or read. The control bus sends signals to memory and I/O devices to enable read and write operations. The pin diagram shows the address and data bus pins as well as control signals of the 8085 microprocessor.
To perform tasks, programs consisting of instruction lists are stored in memory. Individual instructions are fetched from memory into the processor for execution. Data is also stored in memory. The processor contains an ALU, control circuitry, and registers like the instruction register (IR), program counter (PC), memory address register (MAR), and memory data register (MDR). Instructions are fetched from memory based on the PC, decoded and executed, potentially accessing operands from memory via the MAR and MDR and performing operations in the ALU. Results may be written back to memory using the same process.
This document provides an introduction to embedded and real-time systems, focusing on the ARM processor, its architecture and peripherals. It discusses ARM architecture versions and instruction sets. It also covers the differences between Von Neumann and Harvard computer architectures. Real-time applications and the ARM dataflow operation are introduced. Specific topics covered include ARM-based products, ARM nomenclature, ARM features like its 32-bit architecture, load/store model and 3-stage pipeline. It also discusses ARM registers, modes of operation and the program status register.
The document discusses interfacing RS232 with microcontrollers. RS232 uses asynchronous communication and the UART (Universal Asynchronous Receiver/Transmitter) to interface with microcontrollers like the ATmel 89C51. The MAX232 IC is used as a driver to interface RS232 with other devices. Baud rates for communication are set using special function registers in the microcontroller that control the serial port. The baud rate can be doubled by setting the SMOD bit in the PCON register. Data is transmitted by storing it in the serial buffer and cleared the transmit interrupt flag, and received by reading the serial buffer when the receive interrupt flag is set. Functions make it easier to send and receive multiple characters of data through the
The 8086 microprocessor is a 16-bit CPU launched by Intel in 1978. It has a 16-bit data bus and 20-bit address bus, allowing it to access up to 1MB of memory. The 8086 architecture partitions the CPU logic into two functional units - the Bus Interface Unit which handles external transactions, and the Execution Unit which performs decoding and execution. This separation improves processing speed by allowing parallel instruction fetching and execution via pipelining. The 8086 uses memory segmentation to access more memory than its 16-bit registers allow, dividing the 1MB address space into 64KB segments addressed using segment and offset registers.
The document discusses instruction execution in a computer processor. It describes how a processor executes instructions by fetching them from memory using the program counter. The instruction is placed in the instruction register and decoded by the control unit. The control unit then selects components like the ALU to carry out operations. Common components involved in instruction execution are the program counter, memory address register, instruction register, memory buffer register, control unit, arithmetic logic unit, and accumulator. The execution cycle involves fetching the instruction from memory address, decoding it, and then executing the instruction.
This document provides an introduction to embedded systems, including their components, characteristics, and design process. It discusses the selection of processors and memory devices for embedded systems. It also describes structural units in embedded processors, memory management methods, timer and counting devices, watchdog timers, real-time clocks, and the use of in-circuit emulators for debugging embedded systems.
based on stored program design
processor system
CPU
memory
input/output system
input/output devices
secondary storage
manages the instruction-execution cycle
FETCH – DECODE – EXECUTE
coordinates the activities of other devices
8085 MICROPROCESSOR ARCHITECTURE AND ITS OPERATIONSRamaPrabha24
This document discusses the architecture and operations of microprocessors. It focuses on the Intel 8085 microprocessor. The 8085 architecture consists of a register array, ALU and logic group, instruction decoder and encoder, interrupt control group, and serial I/O control group. The register array contains general purpose registers, temporary registers, special purpose registers like the accumulator, flags register, and instruction register, and 16-bit registers like the program counter and stack pointer. The ALU performs arithmetic and logical operations. The instruction decoder decodes instructions and the timing and control circuitry manages the sequencing of operations. Microprocessor operations include memory reads/writes, I/O reads/writes using address, data and control buses, internal data operations
Minimum mode and Maximum mode Configuration in 8086Jismy .K.Jose
The document discusses the minimum and maximum mode configurations of the 8086 microprocessor. In minimum mode, a single 8086 processor controls all signals and there is one microprocessor. In maximum mode, more than one microprocessor is present and status signals determine control signals from a bus controller chip. The document also provides details on the pins, signals, and timing diagrams used in read, write, and bus request cycles for both minimum and maximum mode configurations.
Communication protocols in Embedded Systems. This presentation focused mainly on lower level protocols. Ideal for the beginner to build understanding on these protocols like I2C, USB, SPI etc.
The document discusses various types of computers and their characteristics. It begins by classifying computers based on speed, cost, computational power, and application. It then describes different types of computers like desktop computers, notebook computers, workstations, mainframe systems, server systems, and supercomputers. It also defines basic computer terminology and concepts like hardware, software, memory, storage, inputs, outputs, and processing. The document further explains functional units of a computer like CPU, memory, and bus structure. It concludes with discussing instruction execution, instruction formats, and branching in computer programs.
The document describes a Universal Asynchronous Receiver Transmitter (UART) circuit. A UART allows a computer to communicate with external devices by transmitting serial data. It contains a receiver that takes in serial data and a transmitter that sends out serial data. A baud rate generator is used to synchronize the transmission and reception of bits. The document provides details on the UART components, data encoding, and includes VHDL code for a UART design.
The 80486 microprocessor features an integrated math coprocessor that is 3 times faster than the 80386/387 combination. It has an 8KB internal code and data cache and uses a 168-pin PGA package. New signals support burst mode memory access and bus sharing. The 80486 includes parity checking/generation and additional page table entry bits control internal caching.
The document discusses the architecture of the 8051 microcontroller. It describes the 8051's central processing unit, memory organization, input/output ports, timers/counters, serial port, and interrupts. The 8051 has a CPU, RAM, ROM, and I/O ports integrated into a single chip. It can be programmed to perform control and sensing tasks in embedded systems.
1. The document discusses the topics of computer instructions, timing and control, and the instruction cycle for a basic computer.
2. It describes the three instruction code formats used - memory reference, register reference, and input/output. Memory reference instructions use bits to specify an address and addressing mode. Register reference instructions specify an operation on the accumulator register.
3. The instruction cycle consists of four phases - fetch an instruction, decode the instruction, read the effective address if needed, and execute the instruction.
The document describes the components and functioning of a microprogram sequencer. The microprogram sequencer selects the next address from various sources like the current microinstruction address field, an incremented address, or an external source. It uses multiplexers and registers to select the appropriate next address and load it into the control address register to fetch the next microinstruction from memory. The input logic determines the types of operations the sequencer can perform, such as branching, subroutine calls and returns, and other address sequencing functions.
This document provides an overview of input/output organization in computers. It discusses how computers can communicate with external devices through buses and interfaces. It covers different I/O techniques like programmed I/O, interrupt-driven I/O, and direct memory access. Interrupts allow devices to signal the processor when they need service. DMA controllers can transfer data directly between devices and memory without processor involvement. The document also addresses handling multiple devices, interrupt priorities, and simultaneous interrupt requests.
This document discusses input/output (I/O) organization in computer systems. It covers various I/O techniques including programmed I/O, interrupts, and direct memory access (DMA). Interrupts allow I/O devices to signal the processor asynchronously when data is ready to be transferred. DMA allows high-speed transfer of data between I/O devices and memory without processor involvement. The document also discusses I/O addressing techniques, I/O interface circuits, bus protocols, and arbitration when multiple devices seek to access the bus simultaneously.
The document discusses the bus architecture of the 8085 microprocessor. It covers the bus organization, structure, and key components. The address bus is 16-bits and allows the microprocessor to address up to 65,536 memory locations. The 8-bit data bus is bi-directional and carries data being written or read. The control bus sends signals to memory and I/O devices to enable read and write operations. The pin diagram shows the address and data bus pins as well as control signals of the 8085 microprocessor.
To perform tasks, programs consisting of instruction lists are stored in memory. Individual instructions are fetched from memory into the processor for execution. Data is also stored in memory. The processor contains an ALU, control circuitry, and registers like the instruction register (IR), program counter (PC), memory address register (MAR), and memory data register (MDR). Instructions are fetched from memory based on the PC, decoded and executed, potentially accessing operands from memory via the MAR and MDR and performing operations in the ALU. Results may be written back to memory using the same process.
This document provides an introduction to embedded and real-time systems, focusing on the ARM processor, its architecture and peripherals. It discusses ARM architecture versions and instruction sets. It also covers the differences between Von Neumann and Harvard computer architectures. Real-time applications and the ARM dataflow operation are introduced. Specific topics covered include ARM-based products, ARM nomenclature, ARM features like its 32-bit architecture, load/store model and 3-stage pipeline. It also discusses ARM registers, modes of operation and the program status register.
The document discusses interfacing RS232 with microcontrollers. RS232 uses asynchronous communication and the UART (Universal Asynchronous Receiver/Transmitter) to interface with microcontrollers like the ATmel 89C51. The MAX232 IC is used as a driver to interface RS232 with other devices. Baud rates for communication are set using special function registers in the microcontroller that control the serial port. The baud rate can be doubled by setting the SMOD bit in the PCON register. Data is transmitted by storing it in the serial buffer and cleared the transmit interrupt flag, and received by reading the serial buffer when the receive interrupt flag is set. Functions make it easier to send and receive multiple characters of data through the
The 8086 microprocessor is a 16-bit CPU launched by Intel in 1978. It has a 16-bit data bus and 20-bit address bus, allowing it to access up to 1MB of memory. The 8086 architecture partitions the CPU logic into two functional units - the Bus Interface Unit which handles external transactions, and the Execution Unit which performs decoding and execution. This separation improves processing speed by allowing parallel instruction fetching and execution via pipelining. The 8086 uses memory segmentation to access more memory than its 16-bit registers allow, dividing the 1MB address space into 64KB segments addressed using segment and offset registers.
The document discusses instruction execution in a computer processor. It describes how a processor executes instructions by fetching them from memory using the program counter. The instruction is placed in the instruction register and decoded by the control unit. The control unit then selects components like the ALU to carry out operations. Common components involved in instruction execution are the program counter, memory address register, instruction register, memory buffer register, control unit, arithmetic logic unit, and accumulator. The execution cycle involves fetching the instruction from memory address, decoding it, and then executing the instruction.
This document provides an introduction to embedded systems, including their components, characteristics, and design process. It discusses the selection of processors and memory devices for embedded systems. It also describes structural units in embedded processors, memory management methods, timer and counting devices, watchdog timers, real-time clocks, and the use of in-circuit emulators for debugging embedded systems.
based on stored program design
processor system
CPU
memory
input/output system
input/output devices
secondary storage
manages the instruction-execution cycle
FETCH – DECODE – EXECUTE
coordinates the activities of other devices
8085 MICROPROCESSOR ARCHITECTURE AND ITS OPERATIONSRamaPrabha24
This document discusses the architecture and operations of microprocessors. It focuses on the Intel 8085 microprocessor. The 8085 architecture consists of a register array, ALU and logic group, instruction decoder and encoder, interrupt control group, and serial I/O control group. The register array contains general purpose registers, temporary registers, special purpose registers like the accumulator, flags register, and instruction register, and 16-bit registers like the program counter and stack pointer. The ALU performs arithmetic and logical operations. The instruction decoder decodes instructions and the timing and control circuitry manages the sequencing of operations. Microprocessor operations include memory reads/writes, I/O reads/writes using address, data and control buses, internal data operations
Minimum mode and Maximum mode Configuration in 8086Jismy .K.Jose
The document discusses the minimum and maximum mode configurations of the 8086 microprocessor. In minimum mode, a single 8086 processor controls all signals and there is one microprocessor. In maximum mode, more than one microprocessor is present and status signals determine control signals from a bus controller chip. The document also provides details on the pins, signals, and timing diagrams used in read, write, and bus request cycles for both minimum and maximum mode configurations.
Communication protocols in Embedded Systems. This presentation focused mainly on lower level protocols. Ideal for the beginner to build understanding on these protocols like I2C, USB, SPI etc.
The document discusses various types of computers and their characteristics. It begins by classifying computers based on speed, cost, computational power, and application. It then describes different types of computers like desktop computers, notebook computers, workstations, mainframe systems, server systems, and supercomputers. It also defines basic computer terminology and concepts like hardware, software, memory, storage, inputs, outputs, and processing. The document further explains functional units of a computer like CPU, memory, and bus structure. It concludes with discussing instruction execution, instruction formats, and branching in computer programs.
The document describes a Universal Asynchronous Receiver Transmitter (UART) circuit. A UART allows a computer to communicate with external devices by transmitting serial data. It contains a receiver that takes in serial data and a transmitter that sends out serial data. A baud rate generator is used to synchronize the transmission and reception of bits. The document provides details on the UART components, data encoding, and includes VHDL code for a UART design.
The 80486 microprocessor features an integrated math coprocessor that is 3 times faster than the 80386/387 combination. It has an 8KB internal code and data cache and uses a 168-pin PGA package. New signals support burst mode memory access and bus sharing. The 80486 includes parity checking/generation and additional page table entry bits control internal caching.
The document discusses the architecture of the 8051 microcontroller. It describes the 8051's central processing unit, memory organization, input/output ports, timers/counters, serial port, and interrupts. The 8051 has a CPU, RAM, ROM, and I/O ports integrated into a single chip. It can be programmed to perform control and sensing tasks in embedded systems.
1. The document discusses the topics of computer instructions, timing and control, and the instruction cycle for a basic computer.
2. It describes the three instruction code formats used - memory reference, register reference, and input/output. Memory reference instructions use bits to specify an address and addressing mode. Register reference instructions specify an operation on the accumulator register.
3. The instruction cycle consists of four phases - fetch an instruction, decode the instruction, read the effective address if needed, and execute the instruction.
The document describes the components and functioning of a microprogram sequencer. The microprogram sequencer selects the next address from various sources like the current microinstruction address field, an incremented address, or an external source. It uses multiplexers and registers to select the appropriate next address and load it into the control address register to fetch the next microinstruction from memory. The input logic determines the types of operations the sequencer can perform, such as branching, subroutine calls and returns, and other address sequencing functions.
This document provides an overview of input/output organization in computers. It discusses how computers can communicate with external devices through buses and interfaces. It covers different I/O techniques like programmed I/O, interrupt-driven I/O, and direct memory access. Interrupts allow devices to signal the processor when they need service. DMA controllers can transfer data directly between devices and memory without processor involvement. The document also addresses handling multiple devices, interrupt priorities, and simultaneous interrupt requests.
This document discusses input/output (I/O) organization in computer systems. It covers various I/O techniques including programmed I/O, interrupts, and direct memory access (DMA). Interrupts allow I/O devices to signal the processor asynchronously when data is ready to be transferred. DMA allows high-speed transfer of data between I/O devices and memory without processor involvement. The document also discusses I/O addressing techniques, I/O interface circuits, bus protocols, and arbitration when multiple devices seek to access the bus simultaneously.
This document discusses input/output (I/O) organization and how processors handle communication with I/O devices. It covers several key topics:
1) I/O devices connect to the processor and memory via a shared bus. Each device has a unique address and interface circuitry to recognize its address and coordinate data transfers.
2) Interrupts allow I/O devices to signal the processor asynchronously when they need attention. The processor saves its state and branches to an interrupt service routine before servicing the device and resuming the interrupted program.
3) Techniques like interrupt prioritization, disabling, and vectored addressing help the processor identify the source when multiple devices issue interrupts simultaneously.
This document discusses input/output (I/O) organization in computers. It covers several topics:
- I/O devices can connect to the CPU via a single shared bus using memory-mapped I/O. This allows direct reading/writing of device registers via memory addresses.
- Interrupts allow I/O devices to signal the CPU when an event occurs, so it can pause its current task and service the device. Interrupt handling involves disabling interrupts, servicing the device, then re-enabling interrupts.
- Direct memory access (DMA) allows high-speed transfer of large blocks of data directly between I/O devices and memory without CPU involvement, improving performance over interrupt-driven
The document discusses how I/O devices are accessed in a computer system. I/O devices are connected to the processor and memory via a shared bus. Each device has a unique address and the processor places the address on the address lines to select a device. Interrupts allow I/O devices to signal the processor when they need service, causing the processor to pause its current program and run an interrupt service routine. The processor supports prioritized interrupts and masking to handle multiple simultaneous interrupt requests. Exceptions generalize the interrupt mechanism to handle other events like errors or debugging breakpoints.
1. Interrupts allow I/O devices to signal the processor when they need service. This avoids inefficient polling. When an interrupt occurs, the processor saves its state and executes an interrupt service routine before returning to the interrupted program.
2. Multiple devices can generate interrupts by having separate interrupt request lines or a prioritized daisy chain configuration. Interrupt vectors allow the processor to determine which device needs service.
3. Direct memory access (DMA) allows high-speed transfer of blocks of data between I/O devices and memory without processor involvement, improving throughput for large data transfers.
The document discusses input/output (I/O) organization in computer systems. It describes three common methods for synchronizing data transfers between processors and I/O devices: program-controlled I/O where the processor polls device status, interrupts where devices signal readiness to the processor, and direct memory access where devices transfer data directly to memory. Interrupts allow the processor to perform other tasks while waiting for I/O, and involve saving state before servicing requests. Processors provide interrupt enabling and disabling to control when requests can be accepted.
This document discusses input/output (I/O) in computer systems. It describes how I/O devices connect to the system bus and exchange data with the processor and memory. There are three main mechanisms for I/O - program-controlled polling, interrupts, and direct memory access (DMA). Interrupts allow devices to signal the processor when data is ready, while DMA allows direct transfer of data between a device and memory without processor involvement. The document outlines the implementation of these different I/O mechanisms.
This document provides an overview of IO hardware and how operating systems manage communication with input/output devices. It discusses how device drivers act as interfaces between the OS and different types of hardware. It also describes various techniques for communicating with devices, including using registers, memory-mapped IO, polling, interrupts, DMA, and the roles of controllers. Interrupts allow asynchronous notification to the CPU when devices need attention. DMA offloads data transfers from the CPU. Effective management of IO is important for system performance.
UNIT 5- UNDERSTANDING THE SYSTEM DESIGN PROCESS.pptxLeahRachael
This document provides information about I/O hardware, secondary storage structures, and the system design process. It discusses different types of I/O devices and how they connect to computers via ports and buses. It describes memory-mapped I/O and how devices communicate with the CPU via registers or direct memory access. The document outlines different disk scheduling algorithms like first-come, first-served, shortest seek time first, SCAN and C-SCAN and compares their performance characteristics. It also covers interrupts and how they allow devices to notify the CPU to efficiently handle I/O transfers.
This document provides information on input/output organization and interfaces in a computer system. It discusses different I/O techniques like interrupts and direct memory access. Interrupts allow I/O devices to signal the processor when they need attention. Direct memory access enables high-speed transfer of data directly between I/O devices and memory without processor involvement. The document also describes common I/O bus standards like PCI, SCSI and USB and how they facilitate communication between devices and the computer.
The document discusses input/output (I/O) organization and accessing I/O devices. It describes how multiple I/O devices can connect to the processor and memory via a shared bus. Each device is assigned a unique address. To access a device, the processor places the device's address on the address lines. Interrupts allow I/O devices to alert the processor when they are ready, improving efficiency over polling. Interrupts cause the processor to save its state and execute an interrupt service routine before resuming the original program. Exceptions extend the interrupt concept to handle errors and other events requiring immediate attention.
This document discusses interface definitions and data transfer schemes. It defines an interface as a shared boundary between system elements that allows for input/output communication via signals and protocols. Interface devices meet interface specifications on one side. Data transfer schemes refer to the method of transferring data between a processor and peripheral devices, and include programmed and direct memory access transfers. Programmed transfers involve small data amounts using I/O instructions, while direct memory access allows large block transfers without processor involvement.
This document discusses system organization and input/output device interfaces. It covers several topics:
1. Single bus architecture with memory-mapped I/O and interface circuits to connect devices to the bus.
2. Program-controlled I/O using polling and interrupts to handle asynchronous devices.
3. Direct memory access (DMA) for high-speed transfer of blocks of data between memory and I/O devices.
4. Details of interrupt handling including priorities, nesting, and vectored interrupts.
The document discusses input/output (I/O) processing and the role of the operating system in managing I/O operations and devices. It covers I/O hardware components like ports, buses, and controllers. It also describes the different models for interaction between I/O controllers and CPUs, including polling, interrupts, and direct memory access (DMA). Finally, it discusses I/O application interfaces and blocking vs non-blocking I/O.
This document discusses computer organization and architecture. It provides an overview of the von Neumann architecture, which is a simple structure capable of executing any program given a properly programmed control unit. The key aspects of the von Neumann architecture are that data and instructions are stored in a single memory, the contents of memory can be addressed by location, and execution occurs sequentially from one instruction to the next. The document also describes the typical components of a computer system, including the processor, memory, and input/output devices, and how they are interconnected using a shared bus system with separate address, data, and control lines.
The document discusses input/output (I/O) organization and buses. It describes how I/O devices connect to the processor and memory via a shared bus. It discusses different I/O access methods like memory-mapped I/O and special I/O instructions. It also covers I/O interfaces, interrupts, direct memory access (DMA), and bus arbitration methods.
The document discusses I/O systems and hardware. It describes how I/O devices communicate with computers through ports, buses, and controllers. There are two main methods for I/O - polling and interrupts. Polling involves the CPU repeatedly checking device status, while interrupts allow devices to notify the CPU when ready via an interrupt request line. Interrupts are more efficient and allow the CPU to work on other tasks while waiting. Modern systems implement prioritized interrupts and interrupt handlers to service different devices and events.
This document discusses input/output (I/O) systems in 3 parts:
1) I/O hardware including devices, buses, controllers, polling, and interrupts. Interrupts allow hardware to notify the CPU when a device is ready rather than requiring repeated polling.
2) The application I/O interface including block/character devices, networks, clocks/timers, and blocking/non-blocking I/O.
3) The kernel I/O subsystem which transforms requests to hardware operations, handles scheduling, buffering, caching, error handling and more. Device drivers plug into the OS to support specific devices.
This document discusses various approaches to software reuse, including design patterns, application frameworks, component-based development, and generative programming. Design patterns describe abstract solutions to common problems in a reusable form. Application frameworks provide reusable abstract and concrete classes that can be adapted and extended to create application systems. Conceptual reuse through design patterns and generative programming allows reuse of ideas rather than just code.
This document provides an overview of cluster analysis, including definitions of key concepts, common applications, and descriptions of various clustering methods. It defines cluster analysis as the task of grouping similar data objects into clusters, with the goal of high intra-cluster similarity and low inter-cluster similarity. Several clustering algorithms are summarized, including partitioning methods like k-means and k-medoids, hierarchical agglomerative methods like AGNES, and density-based methods. Evaluation of clustering quality and considerations for applying cluster analysis are also discussed.
Data Mining Concepts and Techniques.pptRvishnupriya2
This document discusses classification techniques for data mining. It covers supervised and unsupervised learning methods. Specifically, it describes classification as a two-step process involving model construction from training data and then using the model to classify new data. Several classification algorithms are covered, including decision tree induction, Bayes classification, and rule-based classification. Evaluation metrics like accuracy and techniques to improve classification like ensemble methods are also summarized.
Data Mining Concepts and Techniques.pptRvishnupriya2
This document discusses classification techniques in data mining, including decision trees. It covers supervised vs. unsupervised learning, the classification process, decision tree induction using information gain and other measures, handling continuous attributes, overfitting, and tree pruning. Specific algorithms covered include ID3, C4.5, CART, and CHAID. The goal of classification and how decision trees are constructed from the training data is explained at a high level.
This document discusses physical storage in database systems. It describes different storage media like cache, main memory, magnetic disks, flash memory, optical disks, and tape storage. Magnetic disks are discussed in detail, covering their structure, performance measures, and optimizations to improve disk access performance. RAID (Redundant Arrays of Independent Disks) techniques are introduced to improve reliability through data redundancy across multiple disks.
The document discusses the history and features of the C programming language. It notes that C was created in 1972 by Dennis Ritchie at Bell Labs and was initially designed for use in UNIX operating systems. Some key points made about C include that it is a general purpose language commonly used for systems programming, that it combines high-level and low-level language features, and that it is portable, widely used, and efficient. The document provides an overview of C's syntax, functions, libraries, and other characteristics that have made it a popular and enduring programming language.
This document provides an overview of computer architecture and digital circuits. It discusses combinational and sequential digital circuits. For combinational circuits, it covers logic gates, Boolean algebra, combinational logic design using multiplexers, decoders and other components. For sequential circuits, it discusses latches, flip-flops, finite state machines, and sequential circuit design. It provides examples of circuit designs for a BCD to 7-segment decoder and a coin reception unit finite state machine. The document is intended to review key concepts in digital logic that are foundational for computer architecture.
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The Indian government has been working over the past few years to include elements of ITS in the transport sector. This standard ensures the optimal operation of the current transport infrastructure. It also increases the efficiency, safety, comfort, and quality of the system. That is why the government created the AIS-140 standard. Compliance with this standard means all vehicles used for public transit must have panic buttons and vehicle tracking modules installed. Nevertheless, in future in the standard protocol of AIS-140 you can expect fare collection and CCTV capabilities.
Get more information here: https://blog.watsoo.com/2023/12/27/all-about-prithvi-ais-140-gps-vehicle-tracker/
Building a Raspberry Pi Robot with Dot NET 8, Blazor and SignalRPeter Gallagher
In this session delivered at NDC Oslo 2024, I talk about how you can control a 3D printed Robot Arm with a Raspberry Pi, .NET 8, Blazor and SignalR.
I also show how you can use a Unity app on an Meta Quest 3 to control the arm VR too.
You can find the GitHub repo and workshop instructions here;
https://bit.ly/dotnetrobotgithub
2. Accessing I / O Devices
Interrupts
Direct Memory Access
Buses
Interface Circuits
2
Outline
3. Content Coverage
Main Memory System
Input/Output System
Arithmetic
and
Logic Unit
Operational
Registers
Program
Counter
Control Unit
Address Data/Instruction
Central Processing Unit (CPU)
Cache
memory
Instruction
Sets
3
4. Accessing I/O Devices
Single-bus structure
The bus enables all the devices connected to it to
exchange information
Typically, the bus consists of three sets of lines used to
carry address, data, and control signals
Each I / O device is assigned a unique set of addresses
Processor
4
.
Memory
I/O device 1 I/O device n
Bus
5. I/O Mapping
5
.
Memory mapped I /O
Devices and memory share an address space
I / O looks just like memory read /write
No special commands for I/ O
Large selection of memory access commands available
Isolated I /O
Separate address spaces
Need I / O or memory select lines
Special commands for I /O
Limited set
6. Memory-Mapped I/O
6
When I / O devices and the memory share the same
address space, the arrangement is called memory-
mapped I /O
With memory-mapped I / O, any machine instruction that
can access memory can be used to transfer data to or from
an I / O device
Most computer systems use memory-mapped I / O.
Some processors have special IN and OUT instructions to
perform I / O transfers
When building a computer system based on these processors, the
designer has the option of connecting I / O devices to usethe
special I / O address space or simply incorporating them as part of
the memory address space
7. I/O Interface for an Input Device
The address decoder, the data and status registers, and
the control circuitry required to coordinate I / O transfers
constitute the device’s interface circuit
Control
circuits
Address
decoder
Data and status
registers
Bus
Address lines
Data lines
Control lines
Input device
7
.
9. Program-Controlled I/O
Consider a simple example of I / O operations
involving a keyboard and a display device in a
computer system. The four registers shown
below are used in the data transfer operations
The two flags KIRQ and DIRQ in STATUS register are
used in conjunction with interrupts
DATAIN
DATAOUT
STATUS
CONTROL
DIRQ KIRQ SOUT SIN
9
DEN KEN
7 6 5 4 3 2 1 0
10. An Example
Move #LINE, R0 Initialize memory pointer
WAITK TestBit #0,STATUS Test SIN
Branch=0 WAITK Wait for character to be entered
Move DATAIN,R1 Read character
WAITD TestBit #1,STATUS Test SOUT
Branch=0 WAITD Wait for display to become ready
Move R1,DATAOUT Send character to display
Move R1,(R0)+ Store character and advance pointer
Compare #$0D,R1 Check if Carriage Return
Branch=0 WAITK If not, get another character
Move #$0A,DATAOUT Otherwise, send Line Feed
Call PROCESS Call a subroutine to process the
input line
A program that reads one line from the keyboard,
stores it in memory buffer, and echoes it back to the
display
10
11. Program-Controlled I/O
11
The example described above illustrates program-
controlled I / O, in which the processor repeatedly
checks a status flag to achieve the required
synchronization between the processor and an input
or output device. We say that the processor polls the
devices
There are two other commonly used mechanisms for
implementing I / O operations: interrupts and direct
memory access
Interrupts: synchronization is achieved by having the I / O
device send a special signal over the bus whenever it is
ready for a data transfer operation
Direct memory access: it involves having the device
interface transfer data directly to or from the memory
12. Interrupts
12
To avoid the processor being not performing any useful
computation, a hardware signal called an interrupt to the
processor can do it.At least one of the bus control lines,
called an interrupt-request line, is usually dedicated for
this purpose An interrupt-service routine usually is needed
and is executed when an interrupt request is issued On
the other hand, the processor must inform the device
that its request has been recognized sothat it may remove
its interrupt-request signal.An interrupt-acknowledge
signal serves this function
14. Interrupt-Service Routine & Subroutine
14
Treatment of an interrupt-service routine is very
similar to that of a subroutine
An important departure from the similarity should
be noted
A subroutine performs a function required by the program
from which it is called.
The interrupt-service routine may not have anything in
common with the program being executed at the time the
interrupt request is received. In fact, the two programs
often belong to different users
Before executing the interrupt-service routine, any
information that may be altered during the execution
of that routine must be saved. This information must
be restored before the interrupted program is
resumed
15. Interrupt Latency
15
The information that needs to be saved and restored
typically includes the condition code flags and the
contents of any registers used by both the interrupted
program and the interrupt-service routine
Saving registers also increases the delay between the
time an interrupt request is received and the start of
execution of the interrupt-service routine. The delay
is called interrupt latency
Typically, the processor saves only the contents of
the program counter and the processor status register.
Any additional information that needs to be saved
must be saved by program instruction at the
beginning of the interrupt-service routine and
restored at the end of the routine
16. Interrupt Hardware
An equivalent circuit for an open-drain bus used
to implement a common interrupt-request line
INTR
INTR1 INTR2 INTRn
Processor
16
INTR
R
Vdd
INTR=INTR1+INTR2+…+INTRn
17. Handling Multiple Devices
17
Handling multiple devices gives rise to a number of
questions:
How can the processor recogniz e the device requesting an
interrupt?
Given that different devices are likely to require different
interrupt-service routines, how can the processor obtain the
starting address of the approp riate routine in each case?
Should a device be allowed to interrupt the processor while
another interrupt is being serviced?
How should two or more simult aneous interrupt request be
handled?
The information needed to determine whether a
device is requesting an interrupt is available in its
status register
When a device raises an interrupt request, it sets to 1 one of
the bits in its status register , which we will call the IRQ bit
18. Identify the Interrupting Device
18
The simplest way to identify the interrupting device
is to have the interrupt-service routine poll all the
I / O devices connected to the bus
The polling scheme is easy to implement. Its main
disadvantage is the time spen t interrogating all the devices
A device requesting an interrupt may identify itself
directly to the processor. Then, the processor can
immediately start executing the corresponding
interrupt-service routine. This is called vectored
interrupts
An interrupt request from a high-priority device
should be accepted while the processor is servicing
another request from a lower-priority device
19. Interrupt Priority
19
The processor’s priority is usually encoded in a few
bits of the processor status word. It can be changed
by program instructions that write into the program
status register (PS). These are privileged instructions,
which can be executed only while the processor is
running in the supervisor mode
The processor is in the su pervisor mode only when
executing operating system routines. It switches to
the user mode before beginning to execute
application program
An attempt to execute a privileged instruction while
in the user mode leads to a special type of interrupt
called a privilege exception
20. Implementation of Interrupt Priority
An example of the implementation of a multiple-
priority scheme
Processor
Device 1 Device 2 Device p
INTA1
INTR1
Priority arbitration
circuit
INTRp
INTAp
20
21. Simultaneous Requests
Consider the problem of simultaneous arrivals of
interrupt requests from two or more devices. The
processor must have some means of deciding
which request to service first
Interrupt priority scheme with daisy chain
Device 1 Device 2 Device n
INTA
INTR
Processor
21
22. Priority Group
Combination of the interrupt priority scheme
with daisy chain and with individual interrupt-
request and interrupt-acknowledge lines
Processor
Priority arbitration
circuit
Device Device Device
INTA1
INTR1
Device Device Device
INTAp
INTRp
22
23. Direct Memory Access
23
To transfer large blocks of data at high speed, a
special control unit may be provided between an
external device and the main memory, without
continuous intervention by the processor. This
approach is called direct memory access (DMA)
DMA transfers are performed by a control circuit that
is part of the I / O device in terface. We refer to this
circuit as a DMA controller.
Since it has to transfer blocks of data, the DMA
controller must increment the memory address for
successive words and keep track of the number of
transfers
24. DMA Controller
Although a DMA controller can transfer data
without intervention by the processor, its
operation must be under the control of a program
executed by the processor
An example
31 30 1 0
Status and control
IRQ
IE
Starting address
Word count
Done
R/W
24
25. DMA Controller in a Computer System
Processor
Main
memory
Disk/DMA
controller
System bus
DMA
controller
Printer Keyboard
Disk Disk
Network
Interface
25
26. Memory Access Priority
26
Memory accesses by the processor and the DMA
controllers are interwoven. Request by DMA devices
for using the bus are always given higher priority
than processor requests.
Among different DMA devices, top priority is given
to high-speed peripherals such as a disk, a high-
speed network interface, etc.
Since the processor originates most memory access
cycles, the DMA controller can be said to “steal”
memory cycles from the processor. Hence, this
interweaving technique is usually called cycle stealing
The DMA controller may transfer a block of data
without interruption. This is called block/burst mode
27. Bus Arbitration
27
A conflict may arise if both the processor and a DMA
controller or two DMA controllers try to use the bus
at the same time to access the main memory. To
resolve this problem, an arbitration procedure on bus
is needed
The device that is allowed to initiate data transfer on
the bus at any given time is called the bus master.
When the current master relinquishes control of the
bus, another device can acquire this status
Bus arbitration is the process by which the next
device to become the bus master take into account
the needs of various devices by establishing a
priority system for gaining access to the bus
28. Bus Arbitration
28
There are two approaches to bus arbitration
Centralized and distributed
In centralized arbitration, a single bus arbiter
performs the required arbitration
In distributed arbitration, all devices participate
in the selection of the next bus master
31. Buses
31
A bus protocol is the set of rules that govern the
behavior of various devices connected to the bus
as to when to place information on the bus, assert
control signals, and so on
In a synchronous bus, all devices derive timing
information from a common clock line. Equal
spaced pulses on this line define equal time
intervals
In the simplest form of a synchronous bus, each
of these intervals constitutes a bus cycle during
which one data transfer can take place
32. A Synchronous Bus Example
t2
32
.
t1
t0
Bus clock
Address and
command
Data
Bus Cycle
Timing of an input transfer on a synchronous bus
33. A Synchronous Bus Example
Detail timing diagram
t2
tAM
Bus clock
Address and
command
Data
t1
tAS
tDM
tDS
t1
Data
Seen by slave
Address and
command
Seen by master
Slave send the
requested data
33
.
34. Input Transfer Using Multiple Clock Cycles
Clock
Address
Command
Data
Slave-ready
34
1 2 3 4
35. Asynchronous Bus
An alternative scheme for controlling data
transfers on the bus is based on the use of a
handshake between the master and slave
Address
and command
Master-ready
Slave-ready
Data
t3 t4 t5
t0 t1 t2
Bus cycle
35
36. Asynchronous Bus
Handshake control of data transfer during an
output operation
Address
and command
Data
t3 t4 t5
t0 t1 t2
Bus cycle
36
Master-ready
Slave-ready
37. Discussion
37
The choice of a particular design involves trade-offs
among factors such as
Simplicity of the device interface
Ability to accommodate device interfaces that introduce different
amounts of delay
Total time required for bus transfer
Ability to detect errors results from addressing a nonexistent
device or from an interface malfunction
Asynchronous bus
The handshake process eliminates the need for synchronization
of the sender and receiver clock, thus simplifying timing design
Synchronous bus
Clock circuitry must be designed carefully to ensure proper
synchronization, and delays must be kept within strict bounds
38. Interface Circuits
Keyboard to processor connection
When a key is pressed, the Valid signal changes from 0
o 1, causing the ASCII code to be loaded into DATAIN
and SIN to be set to 1
The status flag SIN is cleared to 0 when the processor
reads the contents of the DATAIN register
Processor
Encoder
and
Debouncing
circuit
DATAIN
SIN
Input
Interface
Keyboard
switches
Valid
Data
Data
Address
Master-ready
Slave-ready
R/W
38
40. Circuit for the Status Flag Block
Q D
Q
SIN
40
Read-data
Master-ready
1
Valid
Clear
41. Printer to Processor Connection
The interface contains a data register, DATAOUT,
and a status flag, SOUT
The SOUT flag is set to 1 when the printer is ready to accept
another character, and it is cleared to 0 when a new
character is loaded into DATAOUT by the processor
When the printer is ready to acce pt a character, it asserts its
idle signal
Processor
DATAOUT
SOUT
Output
Interface
Data
Address
Master-ready
Slave-ready
R/W Printer
Idle
Data
Valid
41
43. A General 8-Bit Parallel Interface
DATAIN
DATAOUT
Data
Direction
Register
D7
43
D0
P7
P0
44. Output Interface Circuit for a Bus Protocol
Address
decoder
Handshake
control
D7 Q7
D7
SOUT
Printer
data
Load-
data
Read-
status
D1
D0
D1 Q1
D0 Q0
Idle
Valid
A1
A0
Clock
My-
address Timing
Logic
Go
Respond
Go=1
Idle
My-address
44
DATAOUT
R/W
Slave-
ready
A31
45. Timing Diagram for an Output Operation
Go
Slave-ready
Time
1 2 3
Clock
Address
R/W
Data
45
46. Serial Port
46
A serial port is used to connect the processor to
I / O devices that require transmission of data one
bit at a time
The key feature of an interface circuit for a serial
port is that it is capable of communicating in a
bit-serial fashion on the device side and in a bit-
parallel fashion on the bus side
The transformation between the parallel and
serial formats is achieved with shift registers that
have parallel access capability
47. A Serial Interface
Input shift register
DATAIN
DATAOUT
Output shift register
Serial input
47
Serial output
D7
D0