CL-PD6833-VC-A View Datasheet(PDF) - Cirrus Logic
Part Name
Description
MFG CO.
'CL-PD6833-VC-A' PDF : 216 Pages View PDF
CL-PD6833
PCI-to-CardBus Host Adapter
3. INTRODUCTION TO THE CL-PD6833
3.1 System Architecture
This section describes the CL-PD6833 basic architecture in terms of PC Card functions. It first introduces
PC Cards, the PCMCIA (Personal Computer Memory Card International Association), and the PC Card
Standard, and then discusses how the CL-PD6833 complies with the standards. It also describes the
windowing capabilities of the CL-PD6833.
3.1.1
PC Card Basics
PC Cards are credit-card-size peripherals that add memory and I/O capabilities to computers in a rugged,
compact form factor. The PC Card Standard describes specifications for using these memory and I/O
devices as insertable, exchangeable peripherals for personal and handheld computers. The PC Card
Standard is published by the PCMCIA, a non-profit trade association that promotes PC Card technology
by defining technical standards.
There are two types of PC Cards: PC Card 16 (R2) and PC Card 32 (CardBus). PC Card 16 (R2) cards
are 16-bit cards that comply with PCMCIA Standard Releases 2.0, 2.01, and 2.1. In 1995, the PCMCIA
released a standard for PC Cards in conjunction with the standard for the PC Card 16 (R2) architecture,
and renamed the joint standard as PC Card Standard. This joint standard introduced 32-bit operation and
support for PC Card 32 (CardBus) bus mastering cards. PC Card 32 (CardBus) cards are 32-bit cards
that comply with the PC Card Standard first released in February 1995.
The CL-PD6833 implements both PC Card 16 (R2) and PC Card 32 (CardBus) functions. The R2
functions of the CL-PD6833 implement the functions described in the PCMCIA Standard Release 2.1,
while the CardBus functions of the CL-PD6833 are compatible with the PC Card Standard. Under
software control, the CL-PD6833 uses the VS1, VS2, CD1, and CD2 pins in the manner described by the
PC Card Standard to identify and power up the PC Card. The PC Card type (R2 or CardBus) determines
its voltage requirements.
For simpler end-user and vendor implementation of the standard, systems employing the PC Card
Standard should also be backward-compatible with industry-standard PC addressing. The CL-PD6833 is
backward-compatible with PCMCIA Standard Releases 1.0, 2.0, 2.01, and 2.1. The CL-PD6833 is also
compatible with JEIDA 4.1 and earlier standards corresponding with the PCMCIA standards above.
PC Card 16 (R2) cards can have attribute and common memory. Attribute memory indicates to host soft-
ware the capabilities of the PC Card, and it allows host software to change the configuration of the card.
Common memory can be used by host software for any purpose such as flash file system, system mem-
ory, and floppy emulation.
For memory-type PC Card 16 (R2) cards, the memory information must be mapped into the system mem-
ory address space. This is accomplished with a ‘windowing’ technique that is similar to expanded memory
schemes already used in PC systems (for example, LIM 4.0 memory manager).
I/O-type PC Card 16 (R2) cards, such as modems, should also be directly addressable, as if the cards
were I/O devices plugged into the PCI bus. For example, it would be highly desirable to have a PC Card
modem accessible to standard communications software as if it were at a COM port. For COM1, this
would require that the modem be accessed at system I/O address 3F8h–3FFh. The method of mapping
a PC Card I/O address into anticipated areas of PCI I/O space is similar to memory windowing.
June 1998
ADVANCE DATA BOOK v0.3
25
INTRODUCTION TO THE CL-PD6833
Share Link: 
