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An address bus is a bus that is used to specify a physical address. When a processor or DMA-enabled device needs to read or write to a memory location, it specifies that memory location on the address bus (the value to be read or written is sent on the data bus). The width of the address bus determines the amount of memory a system can address.
Bus (computing), a communication system that transfers data between different components in a computer or between different computers Memory bus, a bus between the computer and the memory; PCI bus, a bus between motherboard and peripherals that uses the Peripheral Component Interconnect standard
A system bus is a single computer bus that connects the major components of a computer system, combining the functions of a data bus to carry information, an address bus to determine where it should be sent or read from, and a control bus to determine its operation. The technique was developed to reduce costs and improve modularity, and ...
Address modifiers specify the number of significant address bits, the privilege mode (to allow processors to distinguish between bus accesses by user-level or system-level software), and whether or not the transfer is a block transfer. Below is an incomplete table of address modifiers:
large bus-widths (64/128/256/512/1024 bit). A simple transaction on the AHB consists of an address phase and a subsequent data phase (without wait states: only two bus-cycles). Access to the target device is controlled through a MUX (non-tristate), thereby admitting bus-access to one bus-master at a time.
An initiator has also to provide the data related to the specified address(es) on the Write data channel: the data on WDATA; the "strobe" bits on WSTRB (if present), which conditionally mark the individual WDATA bytes as "valid" or "invalid" Like in the read path, on the last data word, WLAST has to be asserted by the initiator.
The ARINC 629 computer bus was introduced in May 1995 and is used on aircraft such as the Boeing 777, Airbus A330 and Airbus A340 [1] [2] as well as the Airbus A320 series. [ 3 ] The ARINC 629 bus operates as a multiple-source, multiple-sink system; each terminal can transmit data to, and receive data from, every other terminal on the data bus.
The figures below are simplex data rates, which may conflict with the duplex rates vendors sometimes use in promotional materials. Where two values are listed, the first value is the downstream rate and the second value is the upstream rate. The use of decimal prefixes is standard in data communications.