PC Cards

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PC Cards

• Provide expandability to notebook/laptop
  computers
• Credit card-size expansion boards that fits into
  a small slot on notebook/laptop computers
• Developed by the PCMCIA consortium of gt300
  manufacturers (IBM, Toshiba, Apple)

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PC Cards

• Originally designed only for memory cards
• Available PC Cards today
• Memory expansion cards
• Tiny hard disk drives
• Network interface adapters
• Wireless modems
• Sound cards
• MPEG decoders
• CD-ROM controllers
• GPS systems
• etc. etc. etc.

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PC Cards
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Constraints on PC Cards

• Robustness
• Low Power operation
• Power Dissipation
• Multiple Mating Cycles (10000)
• Add-in functions rather than Add-On functions!
• Means PC Cards may be needed for basic computer
  operation

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Card Types

• Small form factor 85.6mm x 54.0mm
• 68-pin connector
• Three card thicknesses supported
• Roughly correspond to different PC Card
  Specifications and Card functionality
• Cards only differ in terms of thickness
• Thinner cards can be used in a thicker slot
• Thicker card cannot be used in a thinner slot

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Card Types
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PC Cards Card Types

• Type I up to 3.3mm thick - Memory Cards
• SRAM, Flash, OTP but NOT DRAM
• Type II up 5mm thick - I/O devices
• Data/fax modems, LAN adapters, mass storage
• most of the available cards today are 5mm cards
• Type III up 10.5mm thick
• Hard disks (latest hard disks are type II)
• Extended cards also available
• Antennas for wireless applications

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PC Card Architecture

• PC Card Standard also defines a software
  architecture
• Provides Plug and Play capability
• Software consists of Socket Services and Card
  Services
• Card and Socket Services allow interoperability
  of PC Cards

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PC Card Evolution

• PC Card Release 1.0Memory only
• PC Card Release 2.XMemory and I/O
• CardBus32-bit high bandwidth interface (133MB/s)

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PC Card Standard Release 1.0

• Interface for Memory Cards only
• Defines Metaformat or Card Information Structure
  (CIS)

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PC Card Release 2.0/2.01/2.1

• I/O interface
• Dual Voltage (3.3V 5V)
• Socket Services Specification
• eXecute In Place (XIP)
• PC Card ATA
• Card Services Specification (2.01)

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PC Card CardBus Standard (1)

• CardBus adds PCI-like performance
• 32-bit bus
• BusMastering interface
• Low Voltage (3.3V)
• Power Management (APM)
• Support for DMA if required
• Multi-function cards

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PC Card CardBus Standard (2)

• Custom Interfaces
• Zoomed Video (ZV)
• Extensions for ISDN, Security and Instrumentation
  Cards

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PC Card Properties

• Card Information Structure (CIS) - describes the
  characteristics of the card so the host can
  configure it
• DMA can be supported if the host allows it
• eXecute In Place - allows OS and Application
  software to run directly from the card
• LV Operation - physical keying prevents 3.3V
  cards from being damaged in 5V slot

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PC Card Properties (2)

• Plug and Play PC Cards can be removed or
  inserted while power is on
• Power and GND contacts pins are the longest
• Make contact before signals
• Power Management - interface to APM through Card
  Services

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PC Card Properties (3)

• Zoomed Video (ZV) - connection between PC Card
  and host system that allows card to write data
  directly to VGA Controller
• Data can be transferred over the ZV bus, not the
  host bus

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PC Card Software Layers

• Two software layers that provide the interface
  between the PC Card adapter and the applications
• Socket ServicesSocket Services layer isolates
  the proprietary aspects of the adapter from the
  software operating above it
• Card ServicesCommunicates with Socket Services
  and is responsible for assigning hardware
  resources to PC Cards

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PC Card Layers
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CardBus Performance

• PC Card-16 8-/16-bit interface at ISA bus speeds
  (8MHz) using ISA-like protocol
• CardBus - 32-bit multiplexed address/data
• Operates at PCI local-bus speeds
• Up to 33 MHz
• Peak bandwidth of 132MB/sec
• CardBus uses the synchronous burst-transfer
  methods of PCI, and a very similar bus protocol
  to PCI

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CardBus Enhancements

• Performance
• Configuration Approach
• Hot-plug capability
• Low-power operation
• Mechanical form-factor

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CardBus Bus Mastering

• PC Card-16 cards can only work as Slaves to
  System resident masters
• CardBus devices can act as system-bus masters
• They can take control of the system bus (or
  buses) to carry out data transfers

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PC Card Configuration

• In the CardBus standard dynamic system
  reconfiguration is a primary functional
  requirement
• Hardware like modem cards can be shared by simply
  porting them from one system to another
• Supports configuration at boot time and/or
  dynamically during run-time
• Plug and Play support using CIS
• (Re)Allocation of system resources when cards are
  added or removed

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CardBus Power Reduction

• Operation at low voltage
• Software control of the clock
• From a CardBus adapter to an attached CardBus
  card
• Provides PCI-like power-management
• Simplifies operation in PCI environment
• CardBus allows for two lower voltage operating
  modes for the future

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CardBus Clock Management

• CardBus includes a "CCLKRUN" signal
• It has an associated protocol for controlling
  clocking to a card
• Allows a PCI-to-CardBus bridge to gate the clock,
  which the bridge supplies to the PC Card
• Allows the card to indicate when it is prepared
  for clocking to stop

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CardBus Mechanical Enhancements

• CardBus cards share PC Card-16's small, thin
  mechanical card design, as well as a similar
  68-pin connector
• CardBus connector design encloses the standard
  68-pin PC Card connector in a ground shield
• If used with controlled edge-rate buffers, the
  shield ensures that ground-bounce does not
  corrupt signals, even at 33 MHz

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PCI CardBus Connectivity
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Zoomed Video

• Connects a video-data stream from a PC Card
  source directly to a host computer's video
  adapter
• Dedicated data path from a system's PC Card
  socket to the video adapter
• Side-band path bypasses the CardBus bridge in
  going from the card socket to the video
  controller
• Through-the-controller path - card video data
  goes through the CardBus bridge on its way to the
  video controller
• In systems that implement ZV, CardBus provides a
  high-speed general-purpose interface, while ZV
  serves as a low-cost video input path

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PCI-CardBus Bridge (1)

• PCI-to-CardBus "bridge" IC - point of attachment
  of the PC Card to the system's PCI bus
• Provides a way of managing the attachment and
  detachment of Cards
• (i.e., bus-isolation buffers and card/socket
  "status-change" notification circuitry)
• Maps several address windows from the card into
  the host system's memory and/or I/O spaces
• Allows the host system to access configuration
  registers on the card

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PCI-CardBus Bridge (2)

• CardBus Bridge is a PCI bus agent so it can
  become Bus Master
• This allows CardBus Bridge to transfer data to
  system memory without CPU intervention
• CardBus supports PCI's PnP auto-configuration.
• Interrupt levels and DMA channels can be
  controlled on a system-wide basis

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PC Cards in a PC

• For the PC, the PC Card just looks like extra
  memory or I/O
• PC Card Specification allows PC Cards to have
  64Mbyte of Common Memory and 64Mbyte of Attribute
  memory 128Mbyte altogether

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Using PC Cards in a PC

• Define an address area in the memory or I/O
  address space of the host system usually called
  a window
• Map a memory or I/O segment of the PC Card into
  the window you have defined
• Access to memory or I/O addresses in the window
  of the hosts address space is redirected to the
  PC Card rather than the hosts own memory or I/O