Portable, non-volatile read/write memory module

• US 4,654,829 A
• Filed: 12/17/1984
• Issued: 03/31/1987
• Est. Priority Date: 12/17/1984
• Status: Expired due to Term

• Current Assignee: Dallas Semiconductor Corporation (Analog Devices, Inc.)
• Original Assignee: Dallas Semiconductor Corporation (Analog Devices, Inc.)
• Inventors: Lee, Robert D., Jiang, Ching-Lin
• Primary Examiner(s): Fears, Terrell W.
• Application Number:
  US06/682,701
• Time in Patent Office: 834 Days
• Field of Search: 365/229, 365/221, 365/226, 235/492, 235/380, 371/66
• US Class Current: 365/189.03
• CPC Class Codes: G11C 5/00 Details of stores covered by group G11C11/00
• CPC Class Codes: G11C 5/141 Battery and back-up supplies
• CPC Class Codes: G11C 7/24 Memory cell safety or protection circuits, e.g. arrangements for preventing inadvertent reading or writing; Status cells; Test cells

Abstract

A portable, non-volatile read/write memory module includes a battery for providing standby power that is coupled to a monolithic integrated circuit. Five terminals of the module are removably connected to a host electronic system for transfer of data to and from the module. One of the terminals is a chip enable input that may optionally be used for providing operating power to the monolithic integrated circuit. The monolithic integrated circuit further includes control circuitry that may optionally be coded for providing a security feature for access to data stored in the memory module.

Claims

1. A non-volatile read/write memory module for use in conjunction with a host electronic system, said host electronic system having a ground voltage-reference node and having a chip enable output node which provides a chip enable signal, comprising:

a battery having first and second terminals;

a monolithic integrated circuit including;

a. a ground terminal coupled to said first battery terminal and adapted for removably making electrical connection to said ground voltage-reference node of said host electronic system;

b. a chip enable input terminal adapted for removably making electrical connection to said chip enable output node of said host electronic system;

c. a serially-accessible read/write data storage means for the storage and retrieval of data;

d. chip enable means coupled to said chip enable input terminal and responsive to said chip enable signal for enabling the serial transfer of data to and from said data storage means; and

e. electronic circuit means coupled to said ground terminal and to said second battery terminal and further coupled to said chip enable input terminal for automatically coupling either said second battery terminal or said chip enable input terminal as the source of power to said data storage means, said electronic circuit means including comparator and switching means for selecting as the source of power whichever of the chip enable input terminal or second battery terminal has the highest voltage; and

a housing for supporting the battery and the integrated circuit, whereby a hand-held, portable module is provided.

4. The module according to claim 1 wherein said monolithic integrated circuit and said host electronic system are electrically connected by no more than five electrical connectors.

2. A non-volatile read/write memory module for use in conjunction with a host electronic system, said host electronic system having a ground voltage-reference node and having a chip enable output node which provides a chip enable signal and having a primary power supply node, comprising:

a battery having first and second terminals;

a monolithic integrated circuit including;

a. a ground terminal coupled to said first battery terminal and adapted for removably making electrical connection to said ground voltage-reference node of said host electronic system;

b. a chip enable input terminal adapted for removably making electrical connection to said chip enable output node of said host electronic system;

c. a serially-accessible read/write data storage means for the storage and retrieval of data;

d. chip enable means coupled to said chip enable input terminal and responsive to said chip enable signal for enabling the serial transfer of data to and from said data storage means;

e. a primary power supply input terminal adapted for removably making electrical connection to said primary power supply node of said host electronic system; and

f. electronic circuit means coupled to said ground terminal and to said second battery terminal and further coupled to said chip enable input terminal and coupled to said primary power supply input terminal for automatically coupling either said second battery terminal or said chip enable input terminal or said primary power supply input terminal as the source of power to said data storage means, said electronic circuit means including comparator and switching means for selecting as the source of power;

(1) the said primary power supply input terminal if the voltage of the said primary power supply input terminal is greater than that of the said second battery terminal, or (2) the said second battery terminal if the voltage of the said second battery terminal is greater than that of both the said primary power supply input terminal and the said chip enable input terminal, or (3) the said chip enable input terminal if the voltage of the said chip enable input terminal is greater than that of both the said primary power supply input terminal and the said second battery terminal; and

a housing for supporting the battery and the integrated circuit, whereby a hand-held, portable module is provided.

5. The module according to claim 2 wherein said monolithic integrated circuit and said host electronic system are electrically connected by no more than five electrical connectors.

3. A non-volatile read/write memory module for use in conjunction with a host electronic system, said host electronic system including serial data generation means for providing a sequence of data bits, comprising:

a battery having first and second terminals;

a monolithic integrated circuit coupled to said first and second terminals of said battery for receiving standby power from said battery and including;

a. a serially-accessible read/write data storage means for the storage and retrieval of data; and

b. control logic means for controlling the serial transfer of data to and from said data storage means, said control logic means including;

i. a data input adapted for serially receiving data bits from said host electronic system;

ii. serial register means coupled to said data input for serially storing a sequence of data bits received by said data input;

iii. read-only circuit means for providing a predetermined bit code, wherein said bit code comprises a plurality of data bits that are not electrically alterable after once having been programmed;

iv. comparison means coupled to said serial register means and coupled to said read-only circuit means for comparing a sequence of data bits stored in said serial register means to said predetermined bit code and for generating a comparison signal that is indicative of whether the said sequence of data bits matches said predetermined bit code; and

v. circuit means responsive to said comparison signal for enabling the writing and reading of data to and from said data storage means; and

a housing for supporting the battery and the integrated circuit, whereby a hand-held, portable module is provided.

6. The module according to claim 3 wherein said monolithic integrated circuit and said host electronic system are electrically connected by no more than five electrical connectors.