| 摘要 |
<p>PURPOSE:To compensate the error of data written on a mask ROM with a programmable ROM and to facilitate the compensation of a program by building in the mask ROM of large capacity and the programmable ROM of small capacity. CONSTITUTION:A data address from an address input terminal 1 is supplied to a mask ROM2 and a programmable logic array 7, and the output of the array 7 is supplied to a programmable ROM9 through an encoder 8. Also, the output of the ROM2 is outputted to a data output terminal 4 through a gate circuit 3, and also, the output of the ROM9 is outputted to the output terminal 4 through a gate circuit 10. Meanwhile, the output of the array 7 is added on an OR circuit 11 and a write circuit 15 to which a write control signal is inputted, and the address of the erroneous data of the ROM2 is set at the array 7. And conductions of the circuits 5 and 10 are controlled by the output of the OR circuit 11, and the error of the data written on the ROM2 is compensated at the ROM9.</p> |
