Electrical computers and digital data processing systems: input/ – Input/output data processing – Input/output command process
Reexamination Certificate
1998-10-30
2001-03-27
Lee, Thomas (Department: 2182)
Electrical computers and digital data processing systems: input/
Input/output data processing
Input/output command process
C710S002000, C710S014000, C700S031000
Reexamination Certificate
active
06209043
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a command-controllable integrated circuit (IC) memory device such as a flash memory and, also, to a method for determining the operational compatibility of the IC memory device with a host system.
2. Description of the Prior Art
FIG. 9
is a block diagram of a conventional IC memory device using M5M29F016 flash memory manufactured by Mitsubishi Denki Kabushiki Kaisha. Note that this IC memory device
100
is used in the form as connected to a host system
110
that controls operation of the IC memory device
100
. A manufacturer code and device code, which are used for determining whether the host
110
is operationally compatible with the IC memory device
100
, are stored at a specific address in the status/ID register
103
of the flash memory. In the example shown, the manufacturer code 1Ch, for example, is stored at address 000000h, and the device code DAh is stored at address 000001h.
The operating mode of the IC memory device
100
is set using commands written to the command user interface (CUI)
102
by the host
110
. One method whereby the host
110
can determine the compatibility of the IC memory device
100
is to apply a specific command, for example, a command 90h in this example, to the CUI
102
of the IC memory device
100
to read the manufacturer code 1Ch and the device code DAh from the status/ID register
103
.
The host
110
then determines whether the IC memory device
100
is compatible based on the manufacturer code 1Ch and the device code DAh returned from the IC memory device
100
. It should be noted that the device codes used for this determination are not limited to codes defined by the Joint Electron Device Engineering Council (JEDEC), and can be any particular code system. The code size is also not specifically limited.
There are cases, however, in which the manufacturer code 1Ch and the device code DAh are set to different values in different IC memory devices that operate according to the same algorithm, use the same commands, and are operationally compatible. An example of such a case is an IC memory device that has been simply reduced in size. The host
110
must therefore recognize these as different IC memory devices, even though the operating algorithms are the same, and devices which are identical in every way except for the manufacturer are assigned different, discrete manufacturer and device codes.
A problem with this method of determining device compatibility is that as a result of using the manufacturer and device codes to determine operational compatibility, a host
110
must specifically recognize the device code of every device with which it is compatible, that is, a potentially large number of codes.
A further problem is that for a host
110
to use the latest IC memory devices, it must also be compatible with the latest manufacturer and device codes.
It should be noted that Japanese Patent Laid-Open Publication No. 57-6491 teaches a semiconductor device that internally compares an identification code written to ROM with an internal identification code, and outputs a specific value when the comparison matches. Note, however, that this semiconductor device does not exchange identification code information with the host.
Note, further, that Japanese Patent Laid-Publication 6-259982 teaches a method and apparatus for rewriting a flash ROM device with the objective of preventing rewrite errors by comparing internal fixed information with information in the rewrite request signal applied from an external device, and returning a specific value to the external device when a match is confirmed.
There is therefore a need for IC memory whereby it can be determined in the IC memory whether the memory is compatible with the manufacturer and device codes of the host.
There is also a need for IC memory whereby compatibility can be determined without it being necessary for the host to store manufacturer and device codes for every IC memory device with which it is compatible.
There is a further need for IC memory whereby host operation can be simplified, and a method for determining operational compatibility of IC memory addressing these needs.
SUMMARY OF THE INVENTION
To meet the above described needs, an IC memory device according to the present invention comprises command-controllable memory and is controlled by a host system. The IC memory device comprises a compatibility information storage unit in which compatibility information is prestored, an identification information storage unit for storing IC memory identification information supplied from a host system, a compatibility checking unit, and a compatibility check result storage unit for storing the result determined by the compatibility checking unit. The compatibility information comprises information for identifying one or more operationally compatible IC memory chips. The compatibility checking unit determines compatibility with host system operation by determining whether the identification information stored to the identification information storage unit is contained in the compatibility information. In response to a request received from the host system, the compatibility check result storage unit supplies the stored result of the compatibility check to the host system.
With the IC memory device according to the present invention, It is therefore not necessary for the host to store a large number of manufacturer codes and device codes. The host can simply read the result of a compatibility check from the IC memory device, and it is therefore not necessary for the host to determine whether it is compatible with a specific IC memory device connected thereto. As a result, the operation of the host can be simplified.
An IC memory device according to another aspect of the present invention is a command-controllable IC memory device comprising a memory unit for storing data from a host system where the IC memory device is controlled by the host system. This IC memory device comprises a compatibility information storage unit in which compatibility information is prestored, an identification information storage unit for storing IC memory identification information supplied from a host system, and a compatibility checking unit for determining compatibility with host system operation by determining whether the identification information stored to the identification information storage unit is contained in the compatibility information. The compatibility information in this aspect of the present invention is also information for identifying one or more operationally compatible IC memory chips.
The compatibility checking unit in this case can supply a specific signal based on a result of a compatibility check to the host system. Alternatively, the compatibility checking unit can stop operation of the memory unit when IC memory operation is determined not compatible with the host system, or can enable data to be only read from the memory unit when IC memory operation is determined not compatible with the host system.
The compatibility information storage unit can alternatively be provided in the memory unit. In this case, the compatibility checking unit determines compatibility with host system operation by reading compatibility information from the memory unit, and determining whether the identification information stored to the identification information storage unit is contained in the compatibility information.
With the IC memory device according to the present invention, It is therefore not necessary for the host to store a large number of manufacturer codes and device codes. The host can simply read the result of a compatibility check from the IC memory device, and it is therefore not necessary for the host to determine whether it is compatible with a specific IC memory device connected thereto. As a result, the operation of the host can be simplified.
When the compatibility checking unit of the IC memory device is designed so as to notify the host system of the compatibility check result by supply
Lee Thomas
Mitsubishi Denki & Kabushiki Kaisha
Nguyen Tanh
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