CardBus
The PCMCIA used the PCI electrical specification
as the basis of a 32-bit, high performance bus interface that utilizes
the existing PCMCIA connector and form-factor. CardBus, or PC-Card 32,
adds bus mastering and high-speed, 32-bit data transfer capabilities to
PCMCIA.
Differences between CardBus and PCI are driven first by the PCMCIA mechanical
environment, and next by the need to make CardBus sockets backward compatible
with PCMCIA R2.x cards. PCI compliant devices are not automatically compliant
with CardBus. The table below summarizes the basic differences between
PCI and CardBus.
PCI and CardBus Comparison |
PARAMETER |
PCI |
CARDBUS |
Access |
Internal |
External |
Vcc |
5V & 3.3V |
3.3V only |
Interface |
Bus |
Point-to-point |
Slew Rate |
1 - 4 V/ns |
0.25 - 1 V/ns |
Tval |
2 - 11 ns |
2 - 18 ns |
Cin |
5 - 12 pF |
10 - 22 pF* |
Max Current |
2A @ 5V/3A @ 3.3V |
1A |
Vih (min) |
0.5 Vcc |
0.475 Vcc |
Interrupts |
4 |
1 |
I/O Drive |
22-ohm load line |
60-ohm load line |
Hot Swapping |
No |
Yes |
Silicon |
PCI |
New for CardBus |
*Loading specified for card; 10pF device buffer assumed. |
An organization known as Yenta has been formed to
help insure interoperability among chip, card, system and software manufacturers
of CardBus products.
For additional information you might try the following:
PCMCIA Headquarters
2635 North First Street, Suite 209
San Jose, CA 95134 USA
Tel (408) 433-CARD (2273)
Fax (408) 433-9558
BBS: (408) 433-2270
EMAIL: office@pcmcia.org
URL: http://www.pc-card.com
PCMCIA European Chapter
Avenue Marcel Thiry 204
B-1200 Brussels, Belgium
Tel +32 2-774-9620
Fax +32 2-774-9690
Yenta
John McGrath
Intel Corporation
2111 NE 25th Street
Hillsboro, OR 97124
Phone: (503) 264-8433
FAX: (503) 264-6055
EMAIL: h_john_mcgrath@ccm.jf.intel.com
More information on Xilinx and PCMCIA.
Passive-Backplane PCI
(See also CompactPCI)
Passive-Backplane PCI (PBPCI) arose out of the industrial user's need
to make off-the-shelf PC hardware more serviceable and easier to upgrade.
This was achieved by defining a system where all add-in cards, including
the mother board, plug into a passive backplane.
The PBPCI specification was designed to allow use of existing desktop
ISA and PCI add-in boards in the backplane without modification. The physical
specification allows both ISA and either 32- or 64-bit PCI connectors to
exist on one side of the board. Backplanes with a dual-bus CPU connector,
1 to 4 PCI connectors and 6 to 15 ISA connectors are available today.
The signals on the PCI interface have the same pin numbers as a PCI
expansion slot. In addition, separate REQ# and GNT# lines are provided
for each PCI slot to support up to four bus masters in one system. Because
PBPCI allows up to 9-in. traces on PCI signals, a PBPCI CPU must provide
a separate clock driver for each PCI slot in order to meet the 2-nsec clock-skew
limit.
For more information regarding CompactPCI or to order a complete specification,
contact the PCI Industrial Computer Manufacturers Group at:
PICMG
301 Edgewater Pl. Ste. 220
Wakefield, MA 01880
Phone: (617) 224-1100
FAX: (617) 224-1239
EMAIL: picmg@rogerscom.com
URL: http://www.picmg.com
CompactPCI
(See also Passive Backplane PCI)
This is a passive backplane specification for PCI designed for industrial
or embedded applications that require a more robust form factor. CompactPCI
is electrically compatible with the PCI specification, allowing the use
of existing PCI chipsets including Xilinx programmable logic and the LogiCORE
PCI Interface.
CompactPCI cards are based on the 3U and 6U Eurocard industry standard
formats. They use high-performance shielded, 2-mm-pitch pin-and-socket
connectors that have lower capacitance than desktop-style PCI edge connectors.
CompactPCI also specifies the use of 10-ohm stub-termination resistors
on signal lines that reduce the effect of board circuits on bus loading.
These differences allow a maximum of eight cards to be put into a single
CompactPCI backplane without the need for a PCI-to-PCI bridge. Use of bridges,
however, allows up to 256 CompactPCI backplanes in a single system.
CompactPCI defines some additional signals on top of the PCI specification
to enhance system operation. These signals provide push putton reset, power
supply status, System Slot identification and legacy IDE interrupt support
features. The standard has provision for 32- and 64-bit interfaces, as
well as 5V and 3.3V signalling. Provision for hat-swapping is also provided,
but many things need to be worked out before that becomes a reality. A
32-bit mezzanine version and form factor is also defined for space constrained
embedded applications.
For more information regarding CompactPCI or to order a complete specification,
contact the PCI Industrial Computer Manufacturers Group
(PICMG). Also see the CompactPCI home page at:
EMAIL: info@compactpci.com
URL: http://www.compactpci.com
IndustrialPCI
IPCI offers a passive-backplane version of PCI in Eurocard (3U and
6U) formats for 19-in rack-mounted systems without all of the additions
imposed by CompactPCI. IPCI is 100% compatible with
the PCI-SIG specification. It supports both 32- and 64-bit PCI through
a single 240-pin connector. The connector has either right angle pins for
backplane applications or straight-pins for a mezzanine stack-through configuration.
It can support a maximum of five slots.
For more information regarding IPCI or to obtain a complete specification,
contact the Standard Industrial PC Systems manufacturers group at:
SiPS e.V.
Krappmuehlstrasse 34
D-68165 Mannheim
Germany
TEL: +49 621 402012
FAX: +49 621 4321430
EMAIL: 100066.62@compuserve.com
URL: http://www.sjps.com
PCI Mezzanine Card (PMC)
PMC is an open standard that provides a slim, modularized mezzanine
card family for low profile computer applications such as VME. By following
the PCI electrical specification, it allows embedded computer designers
to use readily available, low cost PCI components. Provision is made in
the PMC standard to support a full 64 bit PCI bus implementation. The specification
is described in Draft IEEE Spec P1386.1. All Xilinx PCI compliant devices
and design files are suitable for PMC applications.
For additional information you might try the following:
VITA at 602-951-8866
EMAIL: info@vita.com
URL: http://www.vita.com
Small PCI (SPCI)
Originally called Small Form Factor (SFF) PCI, the SPCI specification
is a mechanical definition for a card and connector scheme with a credit
card sized footprint for portable and space restricted applications. It
uses all of the PCI Revision 2.1 signal protocol, electrical and configuration
definitions, except support for 64-bit transfers and JTAG.
There are many physical similarities between SPCI
and PCMCIA cards. Both have the exact same footprint, however SPCI uses
a 108-pin connector versus PCMCIA's 68. Two SPCI card thicknesses are defined;
Type A cards are 5.0 mm thick and Type B cards are 10.5 mm, corresponding
to PCMCIA's Type II and III cards, respectively. These tight form factors
will benefit from smaller device packaging such as the TQ/VQFPs available
from Xilinx.
The specification states that its intent "is to define
cards that are installed at the point of manufacture" and hence do not
include descriptions for protective covers. But since the specification
indicates that covers are not prohibited, it remains to see whether or
not SPCI will compete directly with PCMCIA or CardBus as a user-accesible
form of system expansion.
SPCI supports 5-Volt, 3.3-Volt and universal cards
through a keyed connector scheme. Keying provisions have also been made
to exclude PCMCIA, JEIDA and DRAM cards without damaging connector interfaces.
Revision 1.0 of the specification was released by
the PCI-SIG on May 1, 1996, and may be obtained from that organization. All
Xilinx PCI compliant devices can be used in SPCI applications.
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