ERASE KEY OPERATION SYSTEM IN PROTECT AREA AND UNPROTECT AREA

摘要

PURPOSE:To enable easy handling for the operator, by limiting the function of the erase key in the unprotect area and the protect area, whether data is deleted from the screen or not. CONSTITUTION:At the depression of the data key, the write data is outputted from the first AND gate 1 with the logical sum between the presence of unprotect area and the non-erase key, and it is written in the data memory 5. At the end of write- in, the column register 6 is incremented by +1. Further, at the depression of erase key, the column register is decremented by -1, and the space data is written in the data memory 5 with the logical sum of the erase key and the unprotect area with the second AND gate 3. Accordingly, the function of the erase key at the protect area can be made the same as retrogressing key.