Daisy chain (electrical engineering)

In electrical and electronic engineering a daisy chain is a wiring scheme in which multiple devices are wired together in sequence or in a ring. [1] Other than a full, single loop, which contain internal loops can not be called daisy chains.

Daisy chains may be used for power, analog signals, digital data, or a combination thereof.

The term daisy chain may be used in such series, or as a series of power strips . Other examples of these devices are those based on USB , FireWire , Thunderbolt and Ethernet cables.

Signal transmission

See also: Passthrough

For analog signals , connections usually Consist of a single electrical bus and, Especially in the case of a chain of Many Devices , May require the use of one or more repeaters or amplifiers dans le chain to COUNTERACT attenuation (the natural loss of energy in Such a system). Digital signals between devices can be used on a simple electrical bus, in which case a terminator bus may be needed on the last device in the chain. However, unlike analog signals, because they are discrete signals , they may also be electrically regenerated, but not modified, by any device in the chain.

Types

Computer hardware

Some hardware can be attached to a computing system in a different way, rather than directly to the computing system that uses the component. Only the last component in the chain directly connected to the computing system. For example, chaining multiple components that each has a UART port to each other. The components must also behave cooperatively. eg, only one seizes the communications bus at a time.

  • SCSI is an example of a digital system that is electrically a bus , in the case of external devices, is physically wired as a daisy chain. Since the network is electrically a bus, it has to be terminated and terminated by a terminator in the last device or selecting an option to make the device terminate internally.
  • MIDI devices are usually designed to be wired in a daisy chain. It is normal for both devices to be used for both chaining and wearing. The THRU port transmits information with minimal delay and no alteration, while the OUT port sends a completely regenerated signal and may add, remove, or change messages, at the cost of some delay in doing so. The difference can be found in the signals arriving at different times; if the chain is long enough, it will be distorted so much that the system can become unreliable or non-functional.
  • Some Serial Peripheral Interface Bus (SPI) IC products are designed with daisy chain capability.
  • All JTAG integrated circuits should support daisy chaining according to JTAG daisy chaining guidelines. [2]
  • Thunderbolt (interface) also supports RAID arrays and computer monitors . [3]
  • The Hexbus is the 10-wire bus of Texas Instruments , used in the TI-99 / 4A , CC-40 and TI-74 .

Network topology

Main article: Network topology § Daisy chain

Any particular daisy chain forms one of two network topologies:

  • Linear topology: For example, ABCDE, ABCDE & CMNO (branched at C) are daisy chain.
  • Ring topology: There is a loop connection from the last device to the first. For example, ABCDEA (loop). This is often called a “daisy chain loop”. [4] [5] [6]

System access

Users can daisy chain computing sessions together. Using services such as Telnet or SSH , the user creates a session on a second computer via Telnet, and from the second session, Telnets to a third and so on. Another typical example is the “terminal session inside a terminal session” using RDP . Reasons to create daisy chains include connecting to a system on a non-routed network via a gateway system, preserving sessions on the computer while working on a second computer, to save bandwidth or to improve connectivity on an unstable network by first connecting to a better connected machine. A wholesome purpose is camouflaging activity in cybercrime .

References

  1. Jump up^ maxim-ic.com – Electrical Engineering Glossary Definition for Daisy Chain
  2. Jump up^ ViaTAP user’s manual, chapter Design guidelines for use with ViaTAP
  3. Jump up^ Intel – Thunderbolt I / O technology
  4. Jump up^ “New device network topologies – Daisy-chain and daisy-chain with loop”[1]
  5. Jump up^ IR3508Z data sheet: “The last phase is connected to the IC to complete the daisy chain loop.” [2]
  6. Jump up^ Joel Konicek, Karen Little. “Security, ID systems, and locks: the book on electronic access control” 1997. p. 170: daisy chain loop illustration. [3]

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