| 摘要 |
PROBLEM TO BE SOLVED: To restore characteristics of an internal circuit adjusted by a ROM circuit, in a semiconductor integrated circuit in which characteristics of an internal circuit can be adjusted by a ROM circuit formed by fuses and the like. SOLUTION: This device is provided with an adjustment control circuit, a ROM circuit, and a selecting circuit. The adjustment control circuit activates a first adjusting signal adjusting an internal circuit in accordance with an adjusting signal from the outside. The ROM circuit activates a second adjusting signal adjusting an internal circuit when information adjusting an internal circuit is programmed. The selecting circuit outputs either of the first adjusting signal and the second adjusting signal in accordance with a control signal, and adjusts characteristics of an internal circuit. Therefore, the second adjusting signal is masked by selecting the first adjusting signal, and information previously programmed in the ROM circuit is made invalid. When information is not programmed in the ROM circuit, characteristics of the internal circuit can be easily adjusted without programming information in the ROM circuit. |
