A multidrop bus (MDB) is a
computer bus
In computer architecture, a bus (historically also called a data highway or databus) is a communication system that transfers data between components inside a computer or between computers. It encompasses both hardware (e.g., wires, optical ...
able to connect three or more devices. A process of
arbitration
Arbitration is a formal method of dispute resolution involving a third party neutral who makes a binding decision. The third party neutral (the 'arbitrator', 'arbiter' or 'arbitral tribunal') renders the decision in the form of an 'arbitrati ...
determines which device sends information at any point. The other devices listen for the data they are intended to receive.
Multidrop buses have the advantage of simplicity and extensibility, but their differing electrical characteristics make them relatively unsuitable for high frequency or high bandwidth applications.
In computing
Since 2000, multidrop standards such as
PCI and
Parallel ATA
Parallel ATA (PATA), originally , also known as Integrated Drive Electronics (IDE), is a standard interface designed for IBM PC-compatible computers. It was first developed by Western Digital and Compaq in 1986 for compatible hard drives and C ...
are increasingly being replaced by
point-to-point systems such as
PCI Express
PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe, is a high-speed standard used to connect hardware components inside computers. It is designed to replace older expansion bus standards such as Peripher ...
and
SATA
SATA (Serial AT Attachment) is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard ...
. Modern
SDRAM
Synchronous dynamic random-access memory (synchronous dynamic RAM or SDRAM) is any DRAM where the operation of its external pin interface is coordinated by an externally supplied clock signal.
DRAM integrated circuits (ICs) produced from the ...
chips exemplify the problem of
electrical impedance discontinuity.
Fully Buffered DIMM is an alternative approach to connecting multiple
DRAM
Dram, DRAM, or drams may refer to:
Technology and engineering
* Dram (unit), a unit of mass and volume, and an informal name for a small amount of liquor, especially whisky or whiskey
* Dynamic random-access memory, a type of electronic semicondu ...
modules to a memory controller.
For vending machines
MDB/ICP
MDB/ICP (formerly known as MDB) is a multidrop bus computer networking protocol used within the vending machine industry, currently published by the American
National Automatic Merchandising Association.
ccTalk
The ccTalk multidrop bus protocol uses an
TTL-level asynchronous serial protocol. It uses address randomization to allow multiple similar devices on the bus (after randomisation the devices can be distinguished by their serial number). ccTalk was developed by CoinControls, but is used by multiple vendors.
See also
*
Bus network topology
*
EIA-485
*
1-Wire
*
Open collector
*
I2C
External links
IBM Journal of Research and Development
{{DEFAULTSORT:Multidrop Bus
Computer buses