PD6710 Datasheet, PDF (27/138 Pages) Intel Corporation – ISA-to-PC-Card (PCMCIA) Controllers

ISA-to-PC-Card (PCMCIA) Controllers — PD6710/’22
4.0
Introduction
4.1
System Architecture
This section describes PC Card basics, windowing, interrupts, PD67XX power management,
socket power management, write FIFO, bus sizing, programmable PC Card timing, and ATA and
DMA mode operation.
4.1.1
PC Card Basics
PCMCIA is an abbreviation for Personal Computer Memory Card International Association. PC
Card Standard is a standard for using memory and I/O devices as insertable, exchangeable
peripherals for PCs (personal computers) and handheld computers. For simpler end-user and
vendor implementation of the standard, systems employing PC Card Standard should also be
backward-compatible with industry-standard PC addressing.
Note: The PD67XX is backward-compatible with PCMCIA standards 1.0, 2.0, 2.01, and 2.1. The
PD67XX is also compatible with JEIDA 4.1 and its earlier standards corresponding with the
PCMCIA standards above.
The memory information for memory-type PC Cards must be mapped into the system memory
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).
PC Cards can have attribute and common memory. Attribute memory is used to indicate to host
software 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 memory, and floppy emulation).
I/O-type PC Cards, such as modem network cards, should also be directly addressable, as if the
cards were I/O devices plugged into the system 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 ISA I/O space is done
similarly to memory windowing.
I/O-type PC Cards usually have interrupts that need to be serviced by host software. For the
example of a modem card accessed as if at COM1, software would expect the modem to generate
interrupts on the IRQ4 line. To be sure all interrupts are routed as expected, the PD67XX can steer
the interrupt from the PC Card to one of several standard PC interrupts (see “Interrupts” on page 30
and the “Interrupt and General Control” on page 51).
4.1.2
PD67XX Windowing Capabilities
For full compatibility with existing software, and to ensure compatibility with future memory cards
and software, the PD67XX provides five programmable memory windows per socket and two
programmable I/O windows per socket. These windows can be used by an inserted PC Card to
access ISA memory and I/O space.
Datasheet
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