Buses CPU
In computer science, the term "buses CPU" refers to the system bus that connects the CPU to other components of the computer, such as memory and input/output devices. It serves as a communication pathway for data and instructions to be exchanged between the CPU and these other components. The buses CPU plays a crucial role in the overall functioning and performance of the computer system.
5 Key excerpts on "Buses CPU"
eBook - ePubElectronics Explained
The New Systems Approach to Learning Electronics
- Louis E. Frenzel(Author)
- 2010(Publication Date)
- Newnes(Publisher)
...This means that all bits in a word are transferred simultaneously from one place to another. It takes only a few nanoseconds (one billionth of a second) for all data bits in one register to be moved to another register. The parallel data transfers take place over a data bus. A bus is simply multiple parallel electrical connections from a source to a destination. A number of these buses are contained within the CPU and are known as internal buses. Microprocessors usually have three major buses—a data bus, an address bus, and a control bus. These are made available to external circuits in some micros. A typical 8-bit CPU has an 8-bit data bus and a 16-bit address bus. The data bus sends data to and from the CPU, RAM, ROM, and I/O sections. All data transfers between the CPU and memory or I/O sections take place over the data bus. The address bus drives all of the memory and I/O devices. When an instruction is fetched from RAM or ROM, it is transferred over the data bus from the memory into the instruction register. Any data word retrieved from memory or a peripheral device via the input section also passes over the data bus into the accumulator or GPR. When a store instruction is executed, the word in the accumulator is transmitted over the data bus into RAM. Data can also be transferred from the accumulator over the data bus to an external device such as an LCD. Or, data from an input device such as a keyboard passes over the data bus and is placed into the accumulator. The important point here is that data can move in either direction over the data bus. We say that it is a bidirectional bus. Another key point is that the data bus can be connected to only one data source at a time. Data can originate only at a single source, but it can be sent to one or more destinations...
eBook - ePub- David Johnson(Author)
- 2020(Publication Date)
- CRC Press(Publisher)
...4 The Central Processing Unit Although referred to as the brain of the system, the Central Processing Unit in a normal installation is the unsung hero, buried in a control cabinet, all but forgotten. 4.1 BASIC FUNCTIONALITY In a programmable controller system, the central processing unit (CPU) provides both the heart and the brain required for successful and timely control execution. It rapidly and efficiently scans all of the system inputs, examines and solves the application logic, and updates all of the system outputs. In addition, it also gives itself a checkup each scan to ensure that its structure is still intact. In this chapter we will examine the central processing unit as it relates to the entire system. Included will be the various functional blocks in the CPU, typical scan techniques, I/O interface and memory uses, power supplies, and system diagnostics. 4.2 TYPICAL FUNCTION BLOCK INTERACTIONS In practice, the central processing unit can vary in its architecture, but consists of the basic building block structure illustrated in Figure 4.1. The processor section consists of one or more microprocessors and their associated circuitry. While it is true that some of the older generation programmable controllers were designed without the luxury of using microprocessors, most modern systems use either a single microprocessor such as the 8086 or Z-80, or multiple microprocessors such as the AMD2903, used in a bit slice architecture. This multi-tasking approach is used in the multiple microprocessor system to break the control system tasks into many small components which can be executed in parallel. The result of this approach is to achieve execution speeds that are orders of magnitude faster than their single-tasking counterparts...
eBook - ePub- K.L.S. Sharma(Author)
- 2011(Publication Date)
- Elsevier(Publisher)
...Bus The processor module and the functional modules are placed on the bus for communication, as illustrated in Figure B.2. In this example, the processor supports two busses, internal and external. These busses have no difference logically as far as the communication between the processor and the functional modules is concerned. They differ only in their physical placement. The internal bus is an integrated part of the processor subsystem. Figure B.2 Processor bus. In this setup, the following lines are provided on the bus: • Power lines for supplying the power to the processor and other functional modules • Address lines for addressing the memory locations and the registers in the functional modules • Data lines for carrying the data from memory/functional modules to the processor and vice versa • Control lines for facilitating the read data from the memory/functional modules into the processor and the write data from the processor into the memory/functional modules • Interrupt line for allowing the functional modules to interrupt the processor to draw its attention for some higher priority work • Clock lines for providing the processor-generated clock signals for the functional modules for synchronization of their operations with the processor In this example, only the important lines on the bus essential to understanding the basics of processor function are considered. In practice, there are many more lines on the bus for additional functions. B.2.2...
- Mohamed Rafiquzzaman(Author)
- 2021(Publication Date)
- CRC Press(Publisher)
...These elements are explained in the following in detail. Figure 1.1 shows a simplified block diagram of a microcomputer. FIGURE 1.1 Simplified block diagram of a microprocessor. 1.3.1 The System Bus The system bus contains three buses. These are the address bus, the data bus, and the control bus. These buses connect the microprocessor to each of the memory and I/O elements so that information transfer between the microprocessor and any of the other elements can take place. On the address bus, information transfer normally takes place only in one direction, from the microprocessor to the memory or I/O elements. Therefore, this is called a unidirectional bus. This bus is usually 16 to 32 bits wide. The number of unique addresses that the microprocessor can generate on this bus depends on the width of this bus. For example, for a 16-bit address bus, the microprocessor can generate 2 16 = 65,536 different possible addresses. A different memory location or an I/O element can be represented by each one of these addresses. The data bus is a bidirectional bus, that is, information can flow in both directions, to or from the microprocessor. This bus is normally 8, 16, or 32 bits wide. The control bus is used to transmit signals that are used to synchronize the operation of the individual microcomputer elements. Typical control signals include READ, WRITE, and RESET. Some signals on the control bus such as interrupt signals are unidirectional, while some others such as RESET may be bidirectional. 1.3.2 The Microprocessor The commercial microprocessor, fabricated using the MOS technology, is normally contained in a single chip. The microprocessor is comprised of a register section, one or more ALUs (Arithmetic Logic Units), and a control unit...
eBook - ePubMoving Media Storage Technologies
Applications & Workflows for Video and Media Server Platforms
- Karl Paulsen(Author)
- 2012(Publication Date)
- Routledge(Publisher)
...Further discussion will find that those terms also make reference to “internal memory” and “external memory,” which in turn led to the evolution of network-based storage, that is, NAS and SANs. As comparatively large amounts of RAM are now found even in the simplest of netbooks, personal computers and workstations continue to grow; the lines dividing one form of storage from another have been blurred due in part to the advances and requirements for memory in all forms. KEY CHAPTER POINTS • Parallel and serial buses used for the functioning of storage and peripheral devices • An exploration of the internal computer buses, such as PCI, EISA, and PCI-X • Ports and storage bus standards comprising of SMD, ESDI, SSA, HIPPI, ATA and PATA, IDE, IPI, and SASI • SCSI basics including command sets, identification schemes, arbitration, and bus bandwidth Carrying and Transferring Data In computer architectures, the subsystem that is the carrier or transfer medium between those components inside a computer or between computer subsystems is called a bus. The bus should not be confused with a network, especially when describing the transfer of data or information between computers per se. The name came from electrical systems that called these buses (or busbars) after those physical highways that carried services such as power supply voltages, signaling services, and eventually instructional controls for external systems. Early computer systems utilized physical wiring bundles often arranged as parallel sets of insulated strands called ribbon cables (see Fig...
