| 摘要 |
<p>PURPOSE:To make substantial compensations of fixed information in an ROM easily and securely, by reading a compensation coefficient at need and correcting the fixed information in the ROM. CONSTITUTION:When a voltage dividing circuit 3 is connected at need to set a desired compensating voltage through a variable resistance VR, this voltage is applied to an A/D converter 4 to obtain a compensating signal, which is applied to a microcomputer 1. A corresponding compensation coefficient is looked up in a table and read out of the memory, and a fixed value read out of a mask ROM2 is multiplied by the compensation coefficient to output the product. As a result, substantial compensations of fixed information written in the ROM are made easily and securely.</p> |
