Semiconductor integrated circuit device with built-in arrangement for memory testing
AssigneeHitachi, Ltd.
InventorsKiyoshi Matsubara, Tadashi Yamaura
Life of this patent
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Abstract
A semiconductor integrated circuit device which inhibits the output of programmed data of its built-in memory to external terminals but outputs the result of a comparison of the programmed data with an input signal supplied from a first external terminal to a second external terminal.
Claims23
A semiconductor integrated circuit device including a plurality of external terminals for receiving signals to be supplied to the device and outputting signals from the device, comprising:
- a memory circuit, an output of predetermined programmed data of which is inhibited to said external terminals;
- and
- comparing means for comparing the programmed data read out from said memory circuit with an input signal supplied from one of said external terminal, and including means for outputting a resulting coincidence or discordance signal to one of said external terminals.
An IC card having a semiconductor integrated circuit device including a plurality of external terminals for receiving signals to be supplied to the device or outputting signals from the device, comprising:
- a memory circuit, an output of predetermined programmed data of which is inhibited to said external terminals;
- and
- a comparing circuit including comparing means for comparing the programmed data read out from said memory circuit with an input signal supplied from a first one of said external terminals, and output means for outputting a resulting coincidence or discordance signal to a second one of said external terminals,
- wherein said memory circuit and said comparing circuit are formed to be part of said semiconductor integrated circuit device.
An IC card having a microcomputer comprising:
- a CPU including means for performing predetermined data processing in accordance with a program;
- a memory means for memorizing information constituting the program;
- external terminals provided on a semiconductor integrated circuit device in which the microcomputer is formed;
- a comparing means coupled to at least one of the external terminals and to said memory means for comparing an input signal supplied from said at least one of the external terminals with an output signal read out from the memory means and for forming an output comparing signal based on comparing of said input signal and said output signal;
- output means coupled to said comparing means for delivering an output signal based on the output comparing signal of the comparing means to at least one of the external terminals;
- and
- a bus for connecting at least one of the external terminals with the CPU, the memory means or the comparing means,
- wherein said CPU, said memory means, said external terminals, said comparing means and said output means are formed to be part of said microcomputer.
Dependencies are inferred from the claim text.