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US 5,349,697 AGranted
Radiotelephone including battery-backup random access memory for storing operating code
AssigneeNokia Mobile Phones Ltd.
InventorSakari Pelkonen
Life of this patent
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Abstract
The program code of an object program of a radiotelephone is recorded into a RAM (3) rather than in an EPROM as is conventional. The checking of the program code and the loading of the program from an external device coupled thereto via an external bus is controlled by program recorded in a ROM (4). This allows the program code to be changed and updated as required with time consuming and expensive replacement of a whole memory.
Claims5
A radiotelephone comprising:
- a volatile random access memory (RAM) for storing program code for the radiotelephone;
- a security battery connected to said volatile RAM for assuring continued temporary storage of said program code in the event of a loss of primary power;
- a nonvolatile read only memory (ROM) for containing code used to determine that a state of said program code is correct;
- an internal bus connected to said volatile RAM,
- nonvolatile ROM and connectable to an external bus emanating from a programming device;
- and
- processor means connected to said internal bus and operable upon primary power being applied to said radiotelephone, to be controlled by said code in said nonvolatile ROM to check that said state of said program code in said RAM is acceptable and, if an error is detected, to enter a wait state to await an interconnection of said external bus to said internal bus and a reloading of said program code via said external bus and internal bus from said programming device.
4 more elements
Dependencies are inferred from the claim text.