Semiconductor device preventing writing of prohibited set value to register
AssigneeFujitsu Limited
InventorAkira Miho
Life of this patent
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Abstract
A semiconductor device includes a data hold circuit configured to acquire data from a data bus and hold the data therein in response to assertion of a write signal, a prohibited set value hold circuit configured to store a predetermined prohibited set value, and a comparison circuit coupled to the data hold circuit and the prohibited set value hold circuit, and configured to assert a prohibition signal in response to a match between the prohibited set value stored in the prohibited set value hold circuit and the data held in the data hold circuit, the assertion of the prohibition signal preventing the data from being written to a predetermined register.
Claims10
A semiconductor device, comprising:
- a data hold circuit configured to acquire data from a data bus and hold the data therein in response to assertion of a write signal;
- a prohibited set value hold circuit configured to store a predetermined prohibited set value;
- and
- a comparison circuit coupled to said data hold circuit and said prohibited set value hold circuit, and configured to assert a prohibition signal in response to a match between the prohibited set value stored in said prohibited set value hold circuit and the data held in said data hold circuit, the assertion of the prohibition signal preventing the data from being written to a predetermined register.
A method of controlling writing of data to a register, comprising the steps of:
- transmitting the data to a data bus so as to write the data to the register;
- monitoring the data bus by comparing the data appearing on the data bus with a prohibited set value defined for the register;
- and
- prohibiting the writing of the data to the register in response to detection of a match by said comparing between the data and the prohibited set value.
Dependencies are inferred from the claim text.