A multidrop bus (MDB) is a
computer bus
In computer architecture, a bus (shortened form of the Latin '' omnibus'', and historically also called data highway or databus) is a communication system that transfers data between components inside a computer, or between computers. This ex ...
in which all components are connected to the electrical circuit. A process of
arbitration
Arbitration is a form of alternative dispute resolution (ADR) that resolves disputes outside the judiciary courts. The dispute will be decided by one or more persons (the 'arbitrators', 'arbiters' or 'arbitral tribunal'), which renders the ' ...
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
PCI may refer to:
Business and economics
* Payment card industry, businesses associated with debit, credit, and other payment cards
** Payment Card Industry Data Security Standard, a set of security requirements for credit card processors
* Pro ...
and
Parallel ATA
Parallel ATA (PATA), originally , also known as 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 CD or DVD drives. The connection ...
are increasingly being replaced by
point-to-point systems such as
PCI Express
PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common ...
and
SATA. 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
Fully Buffered DIMM (or FB-DIMM) is a memory technology that can be used to increase reliability and density of memory systems. Unlike the parallel bus architecture of traditional DRAMs, an FB-DIMM has a serial interface between the memory contro ...
is an alternative approach to connecting multiple
DRAM
Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxid ...
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
1-Wire is a device communications bus system designed by Dallas Semiconductor Corp. that provides low-speed (16.3 kbit/s) data, signaling, and power over a single conductor.
1-Wire is similar in concept to I²C, but with lower data rates and ...
*
Open collector
External links
IBM Journal of Research and Development
{{DEFAULTSORT:Multidrop Bus
Computer buses