| 摘要 |
<p>A semiconductor memory device with a mask ROM (56) and a PROM (54) whose program characteristics are different is provided with a switching means (58). The switching operation is performed so that the content of the mask ROM (56) becomes effective when the mask ROM is programmed and so that the content of the PROM (54) becomes effective when the PROM is programmed. Thereby, both mask ROM and PROM become programmable, making the semiconductor memory device with mask ROM and PROM effectively operative.</p> |
