INTEGRATED CIRCUIT AND METHOD OF AUTOMATICALLY SELECTING AN INTERNAL OR AN EXTERNAL NON-VOLATILE MEMORY AS A SOURCE OF PROGRAM CODE RESPONSIVE TO PRESENCE OR ABSENCE OF THE EXTERNAL NON-VOLATILE MEMORY
First Claim
1. A semiconductor device, comprising:
- a single integrated circuit substrate including;
a volatile memory;
an internal non-volatile memory a terminal for optionally coupling an external non-volatile memory device to said semiconductor device; and
a selector system coupled to said internal non-volatile memory and said terminal, wherein said selector system selects a single source from which to load a program code into said volatile memory from among said external non-volatile memory and said internal non-volatile memory device based upon whether or not said external non-volatile memory device is coupled to said terminal, said selector system including;
a coupling detector for detecting whether or not said external non-volatile memory device is coupled to said terminal; and
a source selector, coupled to said coupling detector, for selecting said internal non-volatile memory as said source in response to said coupling detector detecting that said external non-volatile memory device is not coupled to said terminal and for selecting said external non-volatile memory device as said source in response to said coupling detector detecting that said external non-volatile memory device is coupled to said terminal.
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Abstract
The present invention is a semiconductor device that includes a DRAM and an internal mask ROM that are implemented on a single integrated circuit substrate. The semiconductor further includes a terminal coupled to an external ROM and a selector for choosing an external ROM or an internal mask ROM for program code loading. If an external ROM is coupled to the aforementioned terminal, the external ROM is given precedence for use in the loading of the aforementioned program code. The control method of the present invention pertains to a semiconductor device including a DRAM, an internal mask ROM, a terminal coupled to an external ROM, a selector for choosing the first path led from the internal mask ROM or the second path led from the terminal, and a coupling determiner deciding whether or not the terminal is coupled to the external ROM. The control method includes the steps of: (a) deciding whether or not the terminal is coupled to the external ROM; (b) selecting a first path when a terminal is not coupled to the external ROM or a second path when the terminal is coupled to the external ROM; and (c) loading a program code from either the internal mask ROM or the external ROM.
8 Citations
15 Claims
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1. A semiconductor device, comprising:
a single integrated circuit substrate including;
a volatile memory;
an internal non-volatile memory a terminal for optionally coupling an external non-volatile memory device to said semiconductor device; and
a selector system coupled to said internal non-volatile memory and said terminal, wherein said selector system selects a single source from which to load a program code into said volatile memory from among said external non-volatile memory and said internal non-volatile memory device based upon whether or not said external non-volatile memory device is coupled to said terminal, said selector system including;
a coupling detector for detecting whether or not said external non-volatile memory device is coupled to said terminal; and
a source selector, coupled to said coupling detector, for selecting said internal non-volatile memory as said source in response to said coupling detector detecting that said external non-volatile memory device is not coupled to said terminal and for selecting said external non-volatile memory device as said source in response to said coupling detector detecting that said external non-volatile memory device is coupled to said terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for controlling a semiconductor device that includes an internal volatile memory, an internal non-volatile memory, and a terminal for optionally coupling an external non-volatile memory device to the semiconductor device, said method comprising:
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detecting whether or not an external non-volatile memory device is coupled to said terminal;
in response to said detecting, selecting a single one of said internal non-volatile memory and the external non-volatile memory device as a source of a program code, wherein said internal non-volatile memory is selected as the source if the external non-volatile memory device is not coupled to said terminal and the external non-volatile memory device is selected as the source if the external non-volatile storage device is coupled to said terminal; and
loading a program code from said selected source into the internal volatile memory. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A hard disk drive comprising:
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a hard disk recording medium;
a medium driver;
a magnetic head located at the tip of an arm; and
a controller that controls driving of said hard disk recording medium by said medium driver, movement of said arm, and transfer of data to and from said hard disk recording medium via said magnetic head according to a program code, wherein said controller comprises a single integrated circuit substrate including;
a volatile memory;
an internal non-volatile memory;
a terminal for optionally coupling an external non-volatile memory device to said semiconductor device; and
a selector system coupled to said internal non-volatile memory and said terminal, wherein said selector system selects a single source from which to load a program code into said volatile memory from among said external non-volatile memory and said internal non-volatile memory device based upon whether or not said external non-volatile memory device is coupled to said terminal, said selector system including;
a coupling detector for detecting whether or not said external non-volatile memory device is coupled to said terminal; and
a source selector, coupled to said coupling detector, for selecting said internal non-volatile memory as said source in response to said coupling detector detecting that said external non-volatile memory device is not coupled to said terminal and for selecting said external non-volatile memory device as said source in response to said coupling detector detecting that said external non-volatile memory device is coupled to said terminal.
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Specification