| 摘要 |
<p>PURPOSE:To decrease the write-in time, by comparing the data to be written in the rewritable non-volatile semiconductor memory EPROM with the data already memorized in the address to be written in, and by performing write-in when the both are in disagreement. CONSTITUTION:The write-in progam and data are stored in the microcomputer muCM1. The muCM1 is controlled with the tele-typewriter 2, and between the written- in EPROM 3 and the bus line 4, the address input circuit 5, data input and output circuit 6, and mode selection circuit 7 which selects the readout mode, write-in mode or high impedance state, are provided. In this system, the data write-in is made that the data from EPROM 3 is read out, it is compared with the written in data, the write-in for the address is omitted with branching when in agreement, and write-in is executed only when in disagreement. Further, while sequentially checking whether write-in is correctly made or not, the operation is repeated over the entire address. Thus, the write-in time can remarkably be reduced.</p> |
