EP0272848A2
Expired / Lapsed
EP
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Semiconductor device having programmable read only memory cells for specific mode
Assignee: Fujitsu Ltd
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Filing: 1987-12-10
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Granted: —
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Expires: 2007-12-10
Abstract
Abstract A semiconductor device having an internal circuit (5) comprises a program circuit (1) for programming a PROM (2), a discrimination circuit (3) for discriminating the contents of the PROM (2), and a specific mode starting circuit (4) for operating the internal circuit (5) in a specific mode when a specific mode starting signal is output from the discrimination circuit (3). Consequently, the operating mode of semiconductor device can be established and changed by programming and re-programming the PROM (2) without the need for special additional equipment.
Inventors
- 👤 Atsushi Shirakaba Kopo 201 Takeuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 08:58
CPC Classifications
G; G11; G11C; G11C17/00; G11C17/14; G11C17/18; G06; G06F; G06F15/00; G06F15/76; G06F15/78; G06F15/7807; G06F15/7814; G11C16/00; G11C16/02; G11C16/04; G11C16/0408; G11C16/0441; G11C16/06; G11C16/08; G11C16/10; G11C16/32; G11C29/00; G11C29/04; G11C29/08; G11C29/12; G11C29/46
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
131 words
A semiconductor device comprising: an internal circuit (5) for operation under a normal mode and a specific mode, terminals (P0,P1,P2); a programable read only memory (2); a program circuit (1), operatively connected to the terminals (P0,P1,P2) and the programable read only memory (2), for programming the programable read only memory (2) in accordance with potentials applied to the terminals (P0,P1,P2); and, a discrimination circuit (3), operatively connected to the programable read only memory (2), for discriminating contents of the programable read only memory (2) and for outputting a control signal to designate the operating mode of the internal circuit (5), the operating mode of the internal circuit (5) being changed by changing the programming of the programmable read only memory (2) in response to the potentials applied to the terminals (P0,P1,P2).
Claim 2
Dependent Claim
131 words
A semiconductor device comprising: an internal circuit (5) for operation under a normal mode and a specific mode, terminals (P0,P1,P2); a programable read only memory (2); a program circuit (1), operatively connected to the terminals (P0,P1,P2) and the programable read only memory (2), for programming the programable read only memory (2) in accordance with potentials applied to the terminals (P0,P1,P2); and, a discrimination circuit (3), operatively connected to the programable read only memory (2), for discriminating contents of the programable read only memory (2) and for outputting a control signal to designate the operating mode of the internal circuit (5), the operating mode of the internal circuit (5) being changed by changing the programming of the programmable read only memory (2) in response to the potentials applied to the terminals (P0,P1,P2).
Claim 3
Dependent Claim
25 words
A semiconductor device as claimed in claim 1, wherein said terminals (P0,P1,P2) are operatively connected to the internal circuit (5) as input or output terminals.
Claim 4
Dependent Claim
47 words
A semiconductor device as claimed in claim 1 or 2, wherein the programable read only memory (2) comprises a two bit cell configuration memory, and the discrimination circuit outputs the control signal by discriminating a discrepancy between the two bits of data held in the memory (2).
Claim 5
Dependent Claim
37 words
A semiconductor device as claimed in anyone of the preceding claims, wherein the programable read only memory (2) comprises erasable programable read only memory cells, electrically alterable read only memory cells, or fusible read only memory cells.
Claim 6
Dependent Claim
32 words
A semiconductor device as claimed in any one of the predeeding claims, wherein the specific mode comprises a plurality of different modes and the discrimination circuit is capable of discriminating between them.
Claim 7
Dependent Claim
25 words
A semiconductor device as claimed in any of claims 1 to 4, wherein the specific mode comprises a test mode of the internal circuit (5).
Claim 8
Dependent Claim
39 words
A semiconductor device as claimed in any one of the preceding claims, wherein the internal circuit (5) comprises a memory device having a plurality of word lines, and during the specific mode all of the word lines are selected.
Claim 9
Dependent Claim
39 words
A semiconductor device as claimed in any one of the preceding claims, wherein the internal circuit (5) comprises a memory device having a plurality of bit lines, and during the specific mode all of the bit lines are selected.
Claim 10
Dependent Claim
74 words
A semiconductor device as claimed in any one of the preceding claims, wherein the programable read only memory (2) includes a first memory cell (C1) and a second memory cell (C2), the internal circuit being brought to the specific mode from the normal mode when the first memory cell (C1) is programmed, and the internal circuit being brought to the normal mode from the specific mode when the second memory cell (C2) is programmed.
References Cited (Backward Citations)
No citation records indexed.
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