Browse Prior Art Database

MINIATURE CARD REMOVAL DETECTION DESIGN

IP.com Disclosure Number: IPCOM000008367D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2002-Jun-11
Document File: 4 page(s) / 149K

Publishing Venue

Motorola

Related People

Bob Uskali: AUTHOR [+2]

Abstract

A Miniature Card specification was released February of 1996. The Miniature Card is a memory- only expansion card that satisfies the needs for many markets including Audio, Digital Film, Wireless, and Personal Digital Assistants (PDAs). Miniature Card provides a high performance memory bus capable of handling applications that require high speed flash disk drives, execute in place (XIP) memory, DRAM expansion, or ROM applications. Currently, Miniature Card can accommodate up to 64-Megabytes of flash, DRAM, or ROM memory. Miniature Card has a small form factor i.e. one- fourth the size of PCMCIA. It has a pinless connector suited for consumer usage. The Miniature Card specification backed by Intel and AMD has gained support by a large number of device manufactures.

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MOTOROLA Technical Developments

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MINIATURE CARD REMOVAL DETECTION DESIGN

by Bob Uskali and Hal Gorenz

BACKGROUND INFORMATION

  A Miniature Card specification was released February of 1996. The Miniature Card is a memory- only expansion card that satisfies the needs for many markets including Audio, Digital Film, Wireless, and Personal Digital Assistants (PDAs). Miniature Card provides a high performance memory bus capable of handling applications that require high speed flash disk drives, execute in place (XIP) memory, DRAM expansion, or ROM applications. Currently, Miniature Card can accommodate up to 64-Megabytes of flash, DRAM, or ROM memory. Miniature Card has a small form factor i.e. one- fourth the size of PCMCIA. It has a pinless connector suited for consumer usage. The Miniature Card specification backed by Intel and AMD has gained support by a large number of device manufactures.

PROBLEM DESCRIPTION

  A review of the Miniature Card specification has revealed a potential problem especially in PDA applications. Although a means for insertion detection is provided by the Miniature Card specifi- cation, no means of removal detection is provided. This paper addresses the issue of removal detection and provides design rules and implementation examples.

  With the use of a removable memory card such as a PCMICA card or Miniature Card, removal of the card during a critical operating condition can lead to system errors, memory corruption, or "hung" operating states. To ensure orderly opera- tion, a sufftcient removal warning must be provided to allow system operation to account for the card removal event. In certain applications or modes of operation (i.e. device is off), little or no detection warning is required. In other applications or operating modes, a significant warning time is required to allow for hardware and/or software reconfiguration.

For example, take the case of a PDA using a Miniature Card with software execution taking place on the Miniature Card. Removal of the card must be preceded by enough warning to allow time for card software execution to cease and execution to be transferred to the host computer. Lack of proper warning of card removal could have catastrophic system results. The minimum warning duration time is a function of the host device hardware and soft- ware requirements.

PROPOSED SOLUTION

  This invention uses a common electrical detect switch for the device battery compartment and Miniature Card. Since the removal of either the main battery or Miniature Card has the same system implications, a common detection switch and signal can be used.

  As shown in Figure A, a removable compart- ment cover is used to contain and protect the main battery as well as the Miniature Card. When the cover is removed as in Figure B to allow battery or Miniature Card access, an elect...