Inside PC Card. Card: Bus and PCMCIA Design

252 Pages·1996·6.391 MB·English

by  Faisal Imdad-Haque (Auth.)

ECAFERP
PCMCIA PC Card has been one of the fastest growing interfaces in the
computing market. It is now the de facto expansion bus for laptops and
notebooks. The size and ruggedness of the PCMCIA PC Card form factor
also make it appealing in applications and markets that have tradition-
ally shunned peripheral expansion.
When I first started working with PCMCIA products three and a half
years ago, I assumed that the PCMCIA PC Card was a very simple tech-
nology with very little complexity. I was wrong. PC Card technologies re-
quire understanding many different skills from mechanical design to
power supply design. Noise considerations play an extremely important
role in card design. llA these issues need to be considered in PCMCIA de-
signs. The 1995 release of the PC Card standard also encompasses many
new technologies and capabilities. CardBus, multifunction cards, media
storage formats, and power management capabilities are some of the
new technologies.
PCMCIA intentionally kept many aspects of the PC Card standard op-
tional. This leads to some uncertainty, especially about implementation
and compatibility. My purpose in writing this book is to try to minimize
some of the confusion arising from the optional capabilities and to illus-
trate the different design approaches through practical examples. I have
attempted to provide a clear path for designers and engineers so that the
implementation si clear. I hope this book will serve its purpose and be-
come a useful tool for engineers involved with PCMCIA.
My thanks and appreciation go to the people who put their time and
effort into reviews and suggestions for this book. These people are, in no
particular order, Jauher Zaidi, Scott Williams, and Tom Newman.
~Faisal euqaH-dadmI
xiii
1 PCMCIA OVERVIEW
1.1 INTRODUCTION
The PCMCIA PC Card interface is one of the fastest growing interfaces in
the computing world. Today this interface is the expansion bus of choice
for laptop, notebook, and palmtop computers. The acceptance of the
PCMCIA interface in other markets is also increasing rapidly. These mar-
kets include desktop personal computers (PCs), embedded systems, com-
munications, and consumer electronics. The PC Card interface has been
accepted in applications that normally shunned any peripheral expan-
sion capability. These applications include platforms as diverse as medi-
cal instrumentation, set-top boxes, electronic test instrumentation, and
digital cameras. The increasing popularity of PCMCIA standards makes it
essential for engineers to understand the basis for and the application of
this technology.
1.2 PCMClA BACKGROUND
PCMCIA is an acronym for Personal Computer and Memory Card Interna-
tional Association. The association was formed in 1989 by DuPont, Fu-
jitsu, and Poqet Computer to define and promote a standard interface
for memory cards in handheld machines. The memory cards replaced
floppy drives, which because of their bulk and power requirements could
not be used in smaller handheld machines.
In November 1990, release 1.0 was published. The standard later
evolved to support input/output (I/O) cards. PCMCIA defined a standard
interface for the 68-pin memory card form factor. This form factor is now
referred to as the PC Card form factor. The 68-pin connector was origi-
nally defined by the Japan Electronics Industry Development Associa-
tion (JEIDA) for the various incompatible IC cards being marketed
within Japan. Since then, PCMCIA has worked closely with JEIDA to en-
sure that JEIDA and PCMCIA specifications are compatible. In fact, the
2 PCMCIA WEIVREVO
1995 release of the PCMCIA standard is a joint release between PCMCIA
and JEIDA.
Technically, the proper reference to the standard is PC Card standard;
the term PCMCIA is supposed to be used only in reference to the associa-
tion. However, in the industry the term PCMCIA has come to be used to
refer to the standard. In this book the terms PCMCIA and PC Card stan-
dard are used interchangeably.
1.3 PC CARD TECHNOLOGY
The term PC Card 1 as defined refers to a 85.6-mm by 54.0-mm card with
a 68-pin connector. A PC Card plugs into a host slot or socket. Besides pe-
ripheral expansion, the PC Card technology also provides for the follow-
ing capabilities:
(cid:12)9 Compact Form Factor PC Cards are in a credit card form factor
measuring 85.6 mm by 54.0 mm. There are three heights: 3.3-mm
(Type I), 5-mm (Type II), 10.5-mm (Type III). All three types use the
68-pin connector.
(cid:12)9 Hot Insertion Most of the components of the standard are defined
to allow the PC Card to be inserted or removed from a host without
powering down or rebooting the machine. This is different from in-
sertion into a hot socket, in which case the socket Vcc is on. The hot
insertion capability requires the Vcc to be switched and requires a
host software layer to manage insertion, removal events, and re-
source allocation for PC Cards.
(cid:12)9 Automatic Configuration A PC Card is automatically configured
upon insertion and allocated the resources it requires. PCMCIA has
defined configuration space, configuration registers, and tuples that
are used to describe the resource requirements and capabilities of the
card. Together these three items allow a host to automatically config-
ure the PC Card upon insertion.
(cid:12)9 Ruggedness All PC Cards are required to perform under environ-
mental and physical conditions defined in the standard.
1.4 APPLICATIONS
Although the PC Card standard was aimed at palmtop computers, many
other types of platforms have begun to include support for PC Cards.
.1 In this book, CP ,draC ,drac and IC card refer to a AICMCP .drac
1.5 PCMCIA PRODUCTS 3
Table 1.1 CP Card key platforms.
gnitupmoC deddebmE gnitupmoc Communications Consumer scinortcele
Laptops Medical Personal Digital cameras
Notebooks instrumentation communicators Set-top boxes
Sub-notebooks Oscilloscopes Network hubs Electronic organizers
Palmtop computers Logic analyzers Network routers Personal financial
Desktop sCP Aircraft black boxes XBP organizers
Smart and cellular Video games
phones Audio recorders
Cellular base
stations
The list of platforms is very long. Some of the key applications are listed
by market segments in Table 1.1.
1.5 PCMClA PRODUCTS
PCMCIA is implemented in both the PC Cards and host platforms. PC
Cards can be I/O or memory cards such as fax/modem, local area net-
work (LAN), ATA, SRAM, or flash cards. PCMCIA hosts are machines that
implement either a 16-bit PC Card interface or a CardBus interface.
PCMCIA hosts are typically either computer systems or other machines.
PC Card sockets can be found in portable machines such as notebook
PCs, laptops, sub-notebook PCs, and handheld computers.
1.6 TYPES OF CARDS
PC Cards are classified by height and functionality. There are three types
of height classifications (see 1.3). Functionally the cards are classified as
memory or I/O cards. Memory cards use memory interface signals from
the PCMCIA bus and implement a linear memory card. I/O cards use an
additional set of signals from the bus and implement devices mapped
into the PCMCIA I/O address space.
1.7 PC CARD STANDARD
The 1995 release of the PCMCIA PC Card standard defines electrical, me-
chanical, and software specifications for support of memory and I/O ex-
pansion with PC Cards. The standard supports two interfaces:
4 PCMCIA WEIVREVO
(cid:12)9 16-bit PC Card Interface A 16-bit slave only bus originally defined
in release 2.0
(cid:12)9 CardBus A 32-bit high speed bus with support for bus masters
Along with CardBus, the 1995 version of the PC Card standard adds
support for multifunction cards, DMA on 16-bit interfaces, and media
storage formats, especially partitioning for ATA and memory card. The
PC Card standard also defines physical and mechanical characteristics
and software standards. The 1995 version of the PC Card standard con-
sists of the following volumes:
.1 Overview and Glossary Introduction to the PC Card standard
2. Electrical Specifications 16-bit interface and CardBus interface
3. Physical Specifications Mechanical and environmental specifica-
tions
4. Metaformat Specifications A binary image used to describe the
PC Card
5. Card Services Specifications Description of the Card Services Ap-
plications Programming Interface (API)
6. Socket Services Specifications Description of the socket services
API
.7 Media Storage Format Specifications Description of partitioning
schemes for storage
8. PC Card ATA Specifications Description of the ATA implementa-
tion on PCMCIA
9. XIP Specifications Execute in Place (XIP) API
10. Guidelines Implementation suggestions
11. PCMCIA Specific Extensions PCMCIA-defined extensions of the
standard
12. JEIDA Specific Extensions JEIDA-defined extensions of the stan-
dard
Release 1.0 supported only memory Cards such as flash, SRAM cards,
and read-only memory (ROM) cards. Release 2.0 of the standard sup-
ported both memory and I/O cards (also referred to as PC Cards). The
standard also allows for hot insertion and removal as well as software
configuration of PCMCIA cards. Figure 1.1 shows the timelines of the
standards defined by PCMCIA.
Besides meeting hardware specifications the designer of a product that
conforms to PCMCIA also must consider the software components of the
PC Card standard. These software components manage the insertion and
removal of the PC Cards and allow the host system to recognize and
1.8 CP CARD ECAFRETNI SUB 5
Figure 1.1 PC Card standard revision history.
automatically configure the card. Figure 1.2 illustrates the software com-
ponents of PCMCIA.
1.8 PC CARD INTERFACE BUS
The PC Card interface is an important component of the standard. It de-
fines the PC Card electrical specifications and bus protocols. In the 1995
release, the PC Card interface supports two types of busesm16-bit PC
Card and CardBus.
The 16-bit interface is similar in many ways to an Industry Standard
Architecture (ISA) bus, also known as the PC-AT bus. It differs in support-
ing event management capabilities on the bus and autoconfiguration
upon insertion by implementing a Card Information Structure (CIS) and
the corresponding function configuration registers. The 1995 release of
the standard introduces the concept of a function as opposed to a card. A
function is a single I/O or memory capability. This interface also now
supports DMA and will eventually also support Zoom Video and DVB
common interface standards once these are approved.
6 PCMCIA WEIVREVO
Figure 1.2 Software components of the PC Card standard.
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The CardBus standard is a higher performance standard than the 16-
bit interface. It is very similar to Peripheral Component Interconnect
(PCI), except for the form factor and the event management capabilities.
Table 1.2 summarizes the key features of CardBus and 16-bit PC Card.
PCMCIA also defines a CIS. This structure defines the resources
needed by the card for it to be configured by the host. Typically a host
reads the CIS when a card is inserted into the PCMCIA socket, and then
configures the card.
1.9 PC CARD DESIGN ISSUES
The form factor and the nature of the PC Card requires attention to cer-
tain aspects of the design of the PC Card. The main issues are as follows:
Host bridge design
CardBus host design
1.9 CP CARD DESIGN SEUSSI 7
Table 1.2 Summary of 16-bit PC Card and CardBus differences.
16-bit PC card CardBus
,-8 16-bit interface ,-8 16-, and 32-bit interfaces
Non-multiplexed address and data Multiplexed address and data
Slave only bus Slave and master capabilities supported
Asynchronous bus Synchronous bus 33-MHz clock with
dynamic clock management capability
Memory, attribute memory, and I/O Memory, I/O, and configuration spaces
spaces
64 BM of address space 4 BG of address space
Fastest cycle time of 100 ns, 20 MB/sec 133 MB/sec peak transfer rate using burst
transfer rate mode
Type ,I ,II and III form factor Type ,I ,II and III form factor
Function configuration registers to Configuration header and function event
configure and control the PC Card registers to configure and control the PC
interface Card
Pulse or level-triggered interrupts Level triggered interrupts only
Switched Vcc and Vpp lines Switched Vcc and Vpp lines required
recommended
No error checking Parity based error checking
Separate memory-only and I/O interface Single interface
Event management support for STSCHG# Event management support for CSTSCHG
and ,PW BVD1,BVD2,Ready, and for various card and socket events
Wakeup events
Audio binary tone support Audio, binary, and PWM support
Noncacheable and nonexclusive transfers Support for cacheable, and exclusive
transfers
3.3V and VS Vcc 3.3V Vcc only
Voltage sensing to detect Vcc threshold Uses CVS1-2 and CCD1-2# to determine
16-bit PC Card or CardBus PC Card
,PW write ;tcetorp ,DVB battery egatlov ;tceted ,MWP pulse width noitaludom
16-bit PC Card interface host design
Voltage regulator design
PC Card design
16-bit PC Card design
CardBus PC Card design
Multifunction PC Card design
Electrical design of PC Card to minimize switching noise. Ground
bounce is an important issue in PC Card design.
Mechanical designmUnderstand the mechanical components of
card design
Power management issues
8 PCMCIA WEIVREVO
CIS design--Essential for compatibility with Card Services
(cid:12)9
(cid:12)9 Card Services and Socket Services interaction with host and PC Card
1.10 SCOPE OF THIS BOOK
This book provides design and development guidelines for designers of
PCMCIA products. It discusses the PC Card standards from an imple-
mentation point of view and provides design examples. It is not a refer-
ence for standards; readers should refer to the PC Card Standards for the
necessary standard information. The book is divided into the following
nine chapters:
.1 PCMCIA Overview
2. PC Card: The 16-bit Bus
3. CardBus: The 32-bit Bus
4. Interface and Configuration Issues
5. Multifunction Cards
6. PCMCIA Software: An Overview
.7 PC Card: The Mechanical Issues
8. Designing PCMCIA Hosts
9. Designing PC Cards
Chapter 1 provides background on PCMCIA and an overview of the
various specifications provided by PCMCIA. It is an introduction to
PCMCIA.
Chapter 2 discusses the 16-bit PC Card bus and brings out the relevant
implementation issues associated with the bus.
Chapter 3 discusses CardBus and provides a discussion of the key
features and capabilities.
Chapter 4 looks at the insertion and configuration issues in PC Card
implementations. It covers CIS design and the programming model
for both 16-bit and CardBus interfaces.
Chapter 5 discusses implementation of multifunction PC Cards.
Chapter 6 provides an overview of the software issues in PCMCIA. It
discusses Card Services, Socket Services, and other PCMCIA client
software.
Chapter 7 discusses mechanical design issues for a PC Card and
discusses the general options.
Chapter 8 discusses requirements for a PCMCIA host and discusses the
various design options and issues. It covers both CardBus and the
16-bit PC Card interface.
1.11 YEK TERMS 9
Chapter 9 discusses PC Card design issues and presents examples. It
also presents a detailed description of interface design, Printed
Circuit Board (PCB) design, component selection, and electrical
design for both CardBus and 16-bit PC Card.
1.11 KEY TERMS
Adapter~A bridge from a host to a bus
CardBus~The high-performance bus recently added to the PC Card
standard
CardBus PC CardmAn 8-, 16-, or 32-bit card designed to work with
the CardBus interface
Card insertion~The process of inserting a PC Card into a host socket
so that it mates with the host connector
Card removal~The process of removing a PC Card from the host
socket
Card Services~A host software layer that interfaces with Socket Ser-
vices to provide event notification to PC Card-aware software. It also
manages resource conflicts between multiple PC Cards and PC Card
clients.
Client software--PC Card-aware software that is a client of Card Ser-
vices
Function~A single instance of a memory or I/O capability; examples
are Ethernet interface, fax/modem, and SCSI interfaces.
Host~A digital platform that supports an interface to PC Cards
Hot insertionwlnsertion of a PC Card into a host without requiring
the host to be shut down or rebooted
I/O cardsmA type of PC Card that provides I/O capability and may be
mapped into the I/O space
Memory cardmA type of PC Card that contains only memory; exam-
ples are flash memory cards, SRAM cards
Memory-only interfacemA unique interface mode within 16-bit PC
Card bus that supports only the memory space. It is essentially the re-
lease 1.0 interface with WAIT# and RESET added.
Multifunction cardsmA PC Card that contains two or more separate
functions