| 摘要 |
PURPOSE:To increase the degree of freedom of the designing of a device circuit by enabling the polarity of a chip selection input to be inverted. CONSTITUTION:To use a chip selection input CS as a ''1'', a write signal is inputted from a write-in input (a) and through a writing circuit 3, a fuse 2 is blown at a voltage higher than the Zener voltage of a Zener diode 3. In this case, a voltage from a Vcc becomes higher than the earth potential to obtain a positive voltage, which is applied to an EOR gate. Therefore, when the input CS in the ''1'', a -CS is a ''0''. Consequently, an output ''0'' is sent from the EOR gate 1 as the -CS without reference to whether the input CS is the ''0'' or ''1'', and a user inverts the polarity of the input CS freely. |
