| 摘要 |
<p>PURPOSE:To simplify wirings of the circuit, by using the programmable logic array method to set the initial value concerning the initial value set system where the autoclear circuit of the memory circuit in the electronic desk calculator is the object. CONSTITUTION:Prescribed bits of address register 2 are applied to digits F4...F128 other than lower two digits of register 2 through gate circuits OG1...OG6 by receiving the prescribed-level signal from FF circuit 1. Thus, initial values of upper six digits of register 2 are fixed. Next, one of addresses 252...255 is designated by register 2, and these addresses are designated repeatedly unitl the clear signal is released, and the program to clear prescribed memory circuits is stored in these addresses to clear contents of prescribed addresses. As a result, the signal line to supply the clear signal to respective memory circuits for the purpose of utilizing the clear operation for the system control becomes needless, so that wirings can be simplified.</p> |
