INITIALIZING CIRCUITS OF DISK WHEN SEMICONDUCTOR WAFERS ARE LOADED

摘要

PURPOSE: An initializing circuit of a disk is to prevent a wafer and an arm fro being damaged due to the malfunction of a loading/unloading unit. CONSTITUTION: A 74157 integrated circuit is inputted with the first auto initializing signal from a CPU and a manual initializing signal from an end station diagnostic through a logic gate. The 74157 integrated circuit is inputted with the second auto-initializing signal. If any one of the first and second auto-initializing signals and the manual initializing signal becomes to zero, a disk is initialized by output signals from an output terminal of the 74157 integrated circuit and an output terminal of the logic gate. The first OR gate(OR11) combines the output signal of the logic gate through the first inverter(INV11) and the output signal of the 74157 integrated circuit through the second inverter(INV12). The first NAND gate(NAND11) has one side inputted with 5 voltages or 0 voltage and the other side inputted with an output of the first OR gate, so that the gate combines the output to output an initializing signal of the disc. A manual switch(SW12) opens and shuts down the output terminals of the logic gate and first NAND gate.