Method and apparatus for upgrading reprogrammable memory contents in a PCMCIA card

A removable computer card including stored Card Information Structure (CIS) information that defines an interface with said card in a computer system, comprising:

• (a) a specialized single port random access memory (SPRAM) means for storing information under control of a processor in said removable computer card, the SRRAM means configured to receive input via a host data bus, the SPRAM means including a first portion for storing said CIS information, and a second portion for storing data and instructions for said computer system;
• (b) control storage means for storing control access data, said control storage means being coupled to said SPRAM means via a microcontroller bus;
• (c) control means for controlling access requests to said SPRAM means by said computer system, said control means being coupled to said control storage means and said SPRAM means;
• and
• (d) an unlock logic means, responsive to write requests from said computer system, for enabling said computer system write to said SPRAM means.

An upgradable removable computer card comprising:

• (a) a specialized single port random access memory (SPRAM) device, under control of a processor in said removable computer card including a first and a second portion to contain configuration information and instructions for said card, said SPRAM device including
• (a1) a random access memory (RAM) device including said first and second portions of said SPRAM device, said RAM device having a write enable input to enable write access to said first and second portions,
• (a2) a first plurality of selectors coupled to said RAM device, said first plurality of selectors selecting address requests to said RAM device,
• (a3) a second plurality of selectors coupled to said RAM device, said second plurality of selectors selecting data presented to said RAM device,
• (a4) a third plurality of selectors coupled to said RAM device, said third plurality of selectors selecting control signals to said RAM device, and
• (a5) a plurality of logic gates coupled to said RAM device, said plurality of logic gates logically selecting input and output signals to and from said RAM device;
• (b) an SPRAM control registers unit coupled to said SPRAM device, said SPRAM control registers unit containing data to control and monitor said SPRAM device;
• (c) a microcontroller subsystem coupled to said control registers unit, said microcontroller controlling access to said SPRAM device;
• and
• (d) an unlock logic circuit, responsive to said computer system, to enable said computer system to write to said RAM device and replace or alter said configuration information and instructions for said card.

An upgradable removable thin form factor computer card containing configuration information, said card comprising:

• (a) a specialized single port random access memory (SPRAM) device having a first and a second portion to contain upgradable configuration information and instructions for said card, said SPRAM device including
• (a1) a random access memory (RAM) device comprising said first and second portions of said SPRAM device, said RAM device having a write enable input to enable write access to said first and second portions
• (a2) a first plurality of selectors coupled to said RAM device, said first plurality of selectors selecting address requests to said RAM device,
• (a3) a second plurality of selectors coupled to said RAM device, said second plurality of selectors selecting data presented to said RAM device,
• (a4) a third plurality of selectors coupled to said RAM device, said third plurality of selectors selecting control signals to said RAM device,
• (a5) a plurality of logic gates coupled to said RAM device, said plurality of logic gates selecting input and output signals to and from said RAM device, and
• (a6) a plurality of address decoders coupled to said RAM device, said plurality of address decoders decoding addresses;
• (b) an SPRAM control registers unit coupled to said SPRAM device, said SPRAM control registers unit containing data to control and monitor id SPRAM device;
• (c) a microcontroller subsystem coupled to said control registers unit, said microcontroller subsystem controlling access to said SPRAM device;
• and
• (d) an unlock logic circuit, responsive to said computer system, to enable said computer system to write or replace CIS information in said RAM device.

A method for upgrading the memory contents of a removable computer card having a specialized single-port random access memory device (SPRAM) for storing configuration information (CIS) while said card is in operation and a microcontroller for controlling access to said SPRAM device in a host computer, comprising the steps of:

• (a) issuing a write request to said SPRAM device by said host computer via a first bus;
• (b) setting data in a status register in said SPRAM device responsive to said write request;
• (c) asserting an access control signal by said microcontroller via a second bus, to allow said write access by said host computer to said SPRAM device;
• (d) executing an unlock routine by said microcontroller to enable said write access to said SPRAM;
• and
• (e) writing data from said host computer via the first bus to write CIS information into said SPRAM device.