PCMCIA PC Card/Flash Card Software Architecture

Document Revision 3.1
09-Feb-96

Introduction

PCMCIA stands for Personal Computer Memory Card International Association which is the organization that develops the PC CARD standard. This standard is an interface standard that describes the hardware and software for credit card sized computer cards. These include, but are not limited to, Flash memory cards such as the ones offered by Intel Corp. This document provides an overview of the PC CARD architecture and briefly describes Flash related software components of both a full PCMCIA software suite, and a Flash card only 'monolithic' software solution. Information is also provided for the MTD or Memory Technology Driver architecture.

System Requirements

x86 processo r-based (286,386,486, Pentium® Processor, etc. ) PC
i82365SL PCIC-compatible Socket Controller or equivalent
DOS 5.0 or above
Windows* 3.1/95 (if present)

Supported Cards

Intel Series 2 Flash Cards
Intel Series 2+ Flash Cards
Intel Value Series 100 Flash Cards
Intel Miniature Card Flash Cards
Others

PC CARD Overview

There are many software layers to the PC CARD standard and many ways those layers can be implemented. In general, they are briefly described as follows:

Card Services (CS) coordinates access to PC Cards and manages system resources among multiple clients. CS accesses the hardware layer via Socket Services.
Socket Services (SS) provides a standardized interface to the hardware (example: 82365SL PCIC Socket Controller) which controls the sockets for the PC Cards. Socket Services configures sockets for I/O, memory interfaces and controls socket voltage
FTL: Flash Cards such as the Intel S2/S2+ cards require a special block device driver in order to be utilized as a disk drive. This driver, known as the Flash Translation Layer (FTL) handles the special requirements of using flash. It can be installed beneath the MS-DOS FAT file system, making Flash memory media appear as a readable and writeable disk drive. FTL handles, in software, the tasks of sectorizing the flash erase blocks, handling wear leveling issues, etc.
CARDRV (MTDDRV) translates file system requests from any software using its flash host and IOCTL interface into PC CARD Card Services requests, assigns drive letters to PC CARD sockets and returns format and partition characteristics back to the file system. CARDRV/MTDDRV is a memory client of Card Services.

PC CARD Software Architecture for Flash Cards

Memory Technology Driver (MTD) manipulates the memory card. It has card specific knowledge of the physical characteristics of the storage medium and the card's specific programming algorithms to read, write and erase the media. Each MTD registers as a client with Card Services.

Socket Controller (or host controller) manipulates the sockets, system bus timings and manages socket power. The PC Card Interface Controller (PCIC 82365SL) controls PC card memory, address windowing for I/O space and Interrupt steering.

Flash Memory Cards are used in a variety of ways. Primarily, the are used to facilitate high performance disk emulation for the storage of data files and application programs on a purely solid-state removable medium. They are also used to provide the capability to eXecute-In-Place (XIP) directly from the flash memory thereby improving performance and saving the cost of redundant DRAM. In a PC Card software environment, the MTD manipulates the Common Memory Plane (CMP) and Attribute Memory Plane (AMP) of the memory card to provide read, write and erase functionality.
ATA device driver, enabler, or Card Services client supports ATA Type II Flash Disk or ATA Type III Hard Disk PC Cards. The ATA Card Services Client Driver/enabler (not shown) usually loads as a client driver of Card Services.

Advantages of MTDs with Flash Cards

Eliminates the redundant code introduced in the integrated generic CARDRVs, which includes code for all the supported cards.
Each MTD contains information to manipulate the unique design of its corresponding PC card architecture. The MTD is the exclusive expert regarding the knowledge of the PC card type. Therefore, it focuses on providing optimized management of each card's unique architecture.
Modularizing MTDs for specific cards allows flexibility to load selected cards. Loading selected MTDs will minimize the memory space allocated. In the future, run-time loads of selected MTDs will be implemented.
MTDs may be written to load into EMS/XMS/DPMI memory, reducing the overall PC CARD "footprint" of DOS memory. You may choose to develop this code using the iMTD2BAS source code available from Intel.

Typical PC CARD Modifications to the System CONFIG.SYS

SystemSoft typical CardSoft* or CardWizard* Version

devicehigh=c:\cardsoft\ss365sl.exe <Socket Services>

devicehigh=c:\cardsoft\cs.exe <Card Services>

devicehigh=c:\cardsoft\csalloc.exe <SystemSoft specific resource allocation utility >

devicehigh=c:\cardsoft\atadrv.exe <ATA Client Driver SystemSoft>

devicehigh=c:\cardsoft\mti2p.exe <MTD for Intel S2&S2+ SystemSoft>

devicehigh=c:\cardsoft\mtsram.exe <MTD for SRAM SystemSoft>

devicehigh=c:\cardsoft\imtd2bas.exe <optional MTD Intel>

devicehigh=c:\cardsoft\mtddrv.exe <MTD-Manager Client Driver and Flash Host Interface SystemSoft>

devicehigh=c:\cardsoft\ftl.exe <FTL Block Device Dirver SystemSoft>

devicehigh=c:\cardsoft\cardid.exe <`Super' Client driver for I/O cards SystemSoft>

Typical Utilities

CSALLOC (SystemSoft) scans the system configuration and reports available resources.
CARDINFO (SystemSoft) scans the PC CARD slots on a system and reports information pertaining to inserted cards.
The CONFIG (SystemSoft) utility provides a windowed pull-down menu interface allowing the user to configure the system's PC card subsystem and create and manage libraries to change tuple and configuration settings.
MCFORMAT (SystemSoft) creates FTL partitions for Flash memory cards utilizing SystemSoft FTL.
Memory Card Diagnostic Utility (MCDiag) (Intel) runs memory card diagnostics for troubleshooting the PC CARD environment, including the Component Management Registers (CMR) and the Card Information Structure (CIS).

Non-PC Card, Embedded, or Monolithic Architecture Overview

The standalone, or embedded (monolithic) software design provides an ideal solution for embedded applications. The generic design integrates all functionality into a simpler driver structure, which eliminates, or greatly reduces the overhead introduced with the full PC Card architecture.
The development of the iCARDRV1 device driver preceded the development of the PC Card architecture. iCARDRV1 contains all of the functionality required to interface an Intel Series 2 and 2+ Flash memory card to DOS and flash file system or an application that needs to `directly' access flash.
The FTL monolithic driver solution from M-Systems is well suited for use with flash as the storage medium in an embedded application. It is very robust, small footprint, and high performance solution for using flash and flash cards as a 'disk drive'.

FTL (M-Systems) MONOLITHIC ARCHITECTURE	MONOLITHIC ARCHITECTURE

Typical Monolithic Modifications to the System CONFIG.SYS

Embedded / Monolithic Version - Flash Host Interface
devicehigh=c:\intel\icardrv1.exe <Flash Cards>

Embedded / Monolithic Version - M-Systems TrueFFS* FTL
devicehigh=c:\TFFS\PCICSS.COM <PC Card Socket controller software>
devicehigh=c:\TFFS\TFFS.COM /window=D000 /size=8192 <FTL>

Typical Utilities

MCFORMAT (Intel) Format utility for use with iCARDRV1 Flash Host Interface
Memory Card Diagnostic Utility (MCDiag) (Intel) runs memory card diagnostics for troubleshooting the PC CARD environment, including the Component Management Registers (CMR) and the Card Information Structure (CIS). Also used to test and erase flash cards.
TFORMAT (M-Systems) Flash Card FTL Format Utility. Used like the DOS format command except to format flash cards with FTL.
TINFO (M-Systems) FTL Information utility. Used to query the system as to the status of the card, socket, and TrueFFS* FTL software. This utility will give you the drive letter used by the Flash Card and FTL.