PC-based Peripheral Interface by laOi5UU


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Von Neumann computer model:
• Input
• Output
• Memory
• CPU Central Processing Unit
CPU         Memory           Input            Output

                                 Data Bus

                                Control Bus

                                Address Bus

 Von Neumann model of computer architecture
•Hardware is the name given to the physical devices
and circuitry of the computer.

•Software refers to the programs written for the

•Firmware is the term given to programs stored in
ROMs or in Programmable devices which
permanently keep their stored information.
•PLC based Control              • Computer based control

•Microprocessor based control   •Microcontroller based control
• Analog/Digital Interface
To interface two peripherals one of them is digital and the other one is analog we have
to add analog to digital converter (ADC) and digital to analog converter (DAC).

 Analog                             Digital


                           Analog Digital Interface
• Synchronized/Asynchronized Interface
Two important categories of interface are used to connect peripherals: the first one is the
synchronized interface which depends on a clock to order the data transfer. The second
one is the asynchronized interface which can be accomplished without clock. To interface
these peripherals together we need handshaking adaptor which regulates the data exchange
between them.




                     Synchronized/Asynchronized Interface.
• Serial/Parallel Interface
To interface two peripherals one of them is parallel and the second is serial we have
to use parallelizing and serializing stages to connect both of them. The parallelizing
stage converts the serial pulses into parallel data while the serializing stage converts
the parallel data into serial pulses.

        Serial                                   Parallel


                                Parallel Serial Interface
The microprocessor can be interfaced with the
peripherals via several techniques, they are:

• Memory   space interface

• I/O ports interface such as serial and parallel ports

• Direct/internal bus interface using internal buses such as ISA,

• Indirect/external bus interface using external buses such as

Microprocessor             Internal            External
                             Bus                 Bus          Peripheral

                                                          Indirect bus interface


                        Direct bus interface

                 Direct/Indirect Bus Interface
Intel Hub Architecture
Classification of System Bus:
According to Function
• Data Bus
• Control Bus
• Address Bus
According to Location
• Internal / Direct ISA, EISA, PCI, AGP, USB, SCSI, IDE, SATA, …
• External / Indirect GPIB, CAMAC, CAN, …

According to Purpose
• General Purpose Bus
• Special Purpose Bus

The bus is not only a cable connection but also
hardware, bus architecture, protocol, software and
bus controller
PnP: Short for Plug and Play, PnP is an ability of a computer to detect and
configure a new piece of hardware automatically, without the requirement of the
user to physically configure the hardware device with jumpers or dipswitches.

For Plug and Play to operate properly on IBM compatible computers the user
     must have the following:

•    BIOS supporting Plug and Play
•    Operating systems supporting PnP
•    Peripheral with PnP support.

Today all new computers have PnP capabilities. Computers running Microsoft
Windows no longer support non PnP devices.
Throughput (Baud-rate, Speed):
Also known as "communication speed", throughput is a numerical value used to
illustrate the total amount of data transferred being transferred through the
computer or device at that given time. This number is commonly represented in
bits per second (bps) or bytes per second (Bps).
Term used to describe a product that is only compatible with a specific type of
hardware, software, computer or manufacturer. When referring to computer
hardware, it is recommended that you do not choose a proprietary device as it
reduces compatibility and generally the capability of upgrading that product in the
Introduced by IBM, ISA or Industry Standard Architecture was originally an 8-bit
bus that was later expanded to a 16-bit bus in 1984. When this BUS was originally
released it was a proprietary BUS, which allowed only IBM to create peripherals and
the actual interface. However in the early 1980's other manufacturers were creating
the bus.

                                   ISA BUS
Short for Extended Industry Standard Architecture, EISA was announced
September of 1988. EISA is a computer bus designed by 9 competitors to compete with
IBM's MCA BUS. These competitors were AST Research, Compaq, Epson, Hewlett
Packard, NEC, Olivetti, Tandy, WYSE, and Zenith Data Systems.

The EISA Bus provided 32-bit slots at an 8.33 MHz cycle rate for the use with 386DX, or
higher processors. In addition the EISA can accommodate a 16-bit ISA card in the first
row. Unfortunately, while the EISA bus is backwards compatible and is not a proprietary
bus the EISA bus never became widely used and is no longer found in computers today.

                                    The EISA Bus
Introduced by Intel in 1992, revised in 1993 to version 2.0, and later revised in 1995 to
PCI 2.1. PCI is short for Peripheral Component Interconnect and is a 32-bit
computer bus that is also available as a 64-bit bus today. The PCI bus is the most
commonly used and found bus in computers today.

                                  The PCI bus version 2.1
PCI-X is a high performance bus that is designed to meet the increased I/O demands of
technologies such as Fiber Channel, Gigabit Ethernet and Ultra3 SCSI. PCI-X capabilities
• Up to 133 MHz bus speed, 64-Bit bandwidth, 1GB/sec throughput
• More efficient bus operation for easier interface
• Split Transactions allows an indicator device to make only one data request and relinquish
the bus. Instead of constantly needing to poll the bus for a response.
• Byte Count that enables indicator to specify in advance the specific number of bytes
requested, eliminating the inefficiency of speculative prefetches.
• Backwards compatibility

                    PCI X


                                     The PCI-X
Various PCI slots. From top to bottom:
• PCI Express ×4
• PCI Express ×16
• PCI Express ×1
• PCI Express ×16
• Conventional PCI (32-bit)
AGP: Introduced by Intel in 1997, AGP or Advanced Graphic Port is a 32-bit bus
designed for the high demands of 3-D graphics. AGP has a direct line to the computers
memory which allows 3-D elements to be stored in the system memory instead of the
video memory.
For AGP to work in a computer must have the AGP slot which comes with most
Pentium II and Pentium III machines. The computer also needs to be running Windows
95 OSR2.1, Windows 98, Windows 98 SE, Windows 2000, Windows ME or higher.

                                                                             PCI Bus
                        The Advanced Graphic Port, AGP
This is the parallel bus for data transfer from hard disk drives, CD-ROMs,
Tape Backup drives, Zip drives, DVD-ROM, or any ATA peripheral to the IDE
capable computer. Also it is known as Parallel ATA, to contrast with Serial
ATA. The latest version features an 40 pin, 80 wire ribbon cable to connect
motherboards to drives. Each such cable can support up to a maximum of
two devices, with one drive on a cable configured as the master drive, and
the other as the slave. This setting is normally handled by a small jumper
block somewhere on the drive.
Small Computer System Interface, or SCSI (pronounced scuzzy), is a set
of standards for physically connecting and transferring data between
computers and peripheral devices. The SCSI standards define commands,
protocols, and electrical and optical interfaces. SCSI is most commonly used
for hard disks and tape drives, but it can connect a wide range of other
devices, including scanners and CD drives. The SCSI standard defines
command sets for specific peripheral device types; the presence of
"unknown" as one of these types means that in theory it can be used as an
interface to almost any device, but the standard is highly pragmatic and
addressed toward commercial requirements.
SCSI is an intelligent, peripheral,
buffered, peer to peer interface. It
hides the complexity of physical
format. Every device attaches to the
SCSI bus in a similar manner. Up to 8
or 16 devices can be attached to a
single bus. There can be any number
of hosts and peripheral devices but
there should be at least one host.
SCSI uses hand shake signals
between devices, SCSI-1, SCSI-2
have the option of parity error
checking. Starting with SCSI-U160
(part of SCSI-3) all commands and
data are error checked by a CRC32
   First-generation SATA devices often operated at best a little faster than parallel
    ATA/133 devices. Subsequently, a 3 Gbit/s signaling rate was added to the physical layer
    (PHY layer), effectively doubling maximum data throughput from 150 MB/s to 300 MB/s.

   For mechanical hard drives, SATA 3 Gbit/s transfer rate is expected to satisfy drive
    throughput requirements for some time, as the fastest mechanical drives barely saturate
    a SATA 1.5 Gbit/s link.

   SATA Revision 3.0 (SATA 6Gb/s): Serial ATA International Organization presented the
    draft specification of SATA 6 Gbit/s physical layer in July 2008 and ratified its physical
    layer specification on August 18, 2008. The full 3.0 standard (peak throughput about
    600MB/s) was released on May 27, 2009.
USB (Universal Serial Bus) is a new external bus developed by Intel, Compaq, DEC,
IBM, Microsoft, NEC and Northern Telcom and released to the public in 1996 with the
Intel 430HX Triton II Mother Board. USB has the capability of transferring 12 Mbps,
supporting up to 127 devices and only utilizing one IRQ. For PC computers to take
advantage of USB the user must be running Windows 95 OSR2, Windows 98 or
Windows 2000. Linux users also have the capability of running USB with the proper
support drivers installed.

USB cables are hot swappable which allows users to connect and disconnect the cable
while the computer is on without any physical damage to the cable.

  USB Logo                     USB Type A & B                  USB mini
USB 1.0 - The original release of USB supports 127 devices transferring 12 Mbps.

USB 1.1 - Also known as full-speed USB, USB 1.1 is similar to the original release
of USB however minor modifications for the hardware and the specifications. This
version of USB still only supports a rate of 12 Mbps.

USB 2.0 - USB 2.0 also known as hi-speed USB was developed by Compaq,
Hewlett Packard, Intel, Lucent, Microsoft, NEC and Philips and was introduced in
2001. Hi-speed USB is capable of supporting a transfer rate of up to 480 Mbps and
is backwards compatible meaning it is capable of supporting USB 1.0 and 1.1 devices
and cables.

USB 3.0
USB 3.0 was released in November 2008. The standard specifies a maximum
transmission speed of up to 5 Gbit/s (625 MB/s), which is more than 10 times as fast
as USB 2.0 (480 Mbit/s, or 60 MB/s), although this speed is typically only achieved
using powerful professional grade or developmental equipment. USB 3.0 reduces the
time required for data transmission, reduces power consumption, and is backward
compatible with USB 2.0.
USB Architecture:
 Host
    ◦ One host per system
    ◦ Typically the PC in standard USB topology
    ◦ Can be any device in OTG
   Hub
    ◦ Provides connecting ports, power, terminations

   Device/Node (i.e. Slave)
    ◦ Peripheral application
USB Specifications:
 A unique connector
 Hub topology
 Auto detection and configuration
 Low power
 High Performance
 Supports up to 127 external devices
 Provides power
 BW:USB 1.1: 12 Mb/s, USB 2.0: 480 Mb/s
USB Topology:
• Maximum cable length of 30 meters
• Maximum of five non-root hubs
• Only a function is allowed in tier 7
• Maximum of six segments
• Hub at center of each star
• Each segment 5m max
• Tiered star
USB Devices:
  ◦ Simplifies USB Connectivity
  ◦ Detect attach and detach
 Functions
  ◦ USB devices that transmit or receive data
   By Apple
   BW:
    ◦ 400 Mbps
    ◦ 800 Mbps for 1394b
    ◦ Can send more than a CD every 10 sec
   Plug & play
   Support 63 devices
   Provides power
   Digital audio, video, external hard drives, …
 The original FireWire was faster than USB when it came out.
 Transfer rates of up to 400 Mbps.
 The maximum distance between devices is 4.5 meters of cable
 Eventually, FireWire 800 replaced USB 2.0 very easily.
 FireWire 800 had a transfer rate of up to 800 Mbps.
 The maximum distance of cable length between devices is 100
USB 1.1   12Mbps

FW 400    400 Mbps

USB 2.0   480 Mbps

FW 800    800 Mbps

USB 3.0   5 Gbps
                            USB    FireWire
On-bus power                2.5W    45W (!)
Max # devices               127      63
Topology                    Star    Tree
Plug & Play                 Yes      Yes
Peer-to-peer connectivity   No       Yes
Device Cost                 Low     High
Bluetooth is a proprietary open wireless technology standard for exchanging data
over short distances (using short-wavelength radio transmissions in the ISM band
from 2400-2480 MHz) from fixed and mobile devices, creating personal area
networks (PANs) with high levels of security. Created by telecoms vendor Ericsson
in 1994, it was originally conceived as a wireless alternative to RS-232 data
cables. It can connect several devices, overcoming problems of synchronization.

Bluetooth is managed by the Bluetooth Special Interest Group, which has more
than 15,000 member companies in the areas of telecommunication, computing,
networking, and consumer electronics. The SIG oversees the development of the
specification, manages the qualification program, and protects the trademarks. To
be marketed as a Bluetooth device, it must be qualified to standards defined by
the SIG. A network of patents is required to implement the technology and are
only licensed to those qualifying devices; thus the protocol, whilst open, may be
regarded as proprietary.
Radio-frequency identification (RFID) is the use of a wireless non-contact system that uses
radio-frequency electromagnetic fields to transfer data from a tag attached to an object, for
the purposes of automatic identification and tracking. Some tags require no battery and are
powered by the electromagnetic fields used to read them. Others use a local power source
and emit radio waves (electromagnetic radiation at radio frequencies). The tag contains
electronically stored information which can be read from up to several metres (yards) away.
Unlike a bar code, the tag does not need to be within line of sight of the reader and may be
embedded in the tracked object.

RFID tags are used in many industries. An RFID attached to an automobile during production
can be used to track its progress through the assembly line. Pharmaceuticals can be tracked
through warehouses. Livestock and pets may have tags injected, allowing positive
identification of the animal. RFID identity cards can give employees access to locked areas of
a building, and RF transponders mounted in automobiles can be used to bill motorists for
access to toll roads or parking.

Since RFID tags can be attached to clothing, possessions, or even implanted within people,
the possibility of reading personally-linked information without consent has raised privacy
Near field communication (NFC) is a set of standards for smart phones and
similar devices to establish radio communication with each other by touching
them together or bringing them into close proximity, usually no more than a few
centimetres. Present and anticipated applications include contactless
transactions, data exchange, and simplified setup of more complex
communications such as Wi-Fi. Communication is also possible between an NFC
device and an unpowered NFC chip, called a "tag“.

NFC standards cover communications protocols and data exchange formats, and
are based on existing radio-frequency identification (RFID) standards including
ISO/IEC 14443 and FeliCa. The standards include ISO/IEC 18092 and those
defined by the NFC Forum, which was founded in 2004 by Nokia, Philips and
Sony, and now has 150 members. The Forum also promotes NFC and certifies
device compliance.

NFC builds upon RFID systems by allowing two-way communication between
endpoints, where earlier systems such as contactless smart cards were one-way
only. Since unpowered NFC "tags" can also be read by NFC devices, it is also
capable of replacing earlier one-way applications.
• In 1965, Hewlett-Packard designed the Hewlett-Packard Interface Bus ( HP-
IB ) to connect their line of programmable instruments to their computers.
Because of its high transfer rates (nominally 1 Mbytes/s), this interface bus
quickly gained popularity. It was later accepted as IEEE Standard 488-1975, and
has evolved to ANSI/IEEE Standard 488.1-1987.
•Today, the name G eneral Purpose Interface Bus (GPIB) is more widely used
than HP-IB. ANSI/IEEE 488.2-1987 strengthened the original standard by
defining precisely how controllers and instruments communicate.
•Standard Commands for Programmable Instruments (SCPI ) took the
command structures defined in IEEE 488.2 and created a single, comprehensive
programming command set that is used with any SCPI instrument. Figure 1
summarizes GPIB history.
 GPIB can connect 15 instruments (0~31 address can be assigned)
  to a PC (controller). The PC handles the transmission on the bus.
 8 bits parallel transmission, up to 8 Mbits/s transmission speed.
 The total cable length in a system should not exceed 20m (2m
  max. between a device and next device)
 Text mode commands. (Easy to differentiate)
 Using three handshake line for handshaking to ensure data
  transmission accuracy.
                                  Function generator


Digital multi-meter                    Switch
                       GPIB Connections

Linear Configuration                      Star Configuration
Controller–area network (CAN or CAN-bus) is a vehicle bus standard
designed to allow microcontrollers and devices to communicate with each
other within a vehicle without a host computer. The CAN Bus is an
automotive bus developed by Robert Bosch, which has quickly gained
acceptance into the automotive and aerospace industries. CAN is a serial
bus protocol to connect individual systems and sensors as an alternative to
conventional multi-wire looms. It allows automotive components to
communicate on a single or dual-wire networked data bus up to 1Mbps.
In 2006, over 70% of all automobiles
sold in North America will utilize CAN
Bus technology. Beginning in 2008,
the Society of Automotive Engineers
(SAE) requires 100% of the vehicles
sold in the USA to use the CAN Bus
communication protocol while the
European Union has similar laws.
Several new after market devices
have been introduced into the market
that utilize the CAN Bus protocol but
until now, there have been no new
devices that assist the aging after
market remote starter and alarm
system technology. Now there is an
after market module that offers
remote starter and alarm connectivity
to the CAN Bus communication
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