| 摘要 |
PURPOSE:To reduce the number of signal transmission lines by distributing a reset signal R, a clock C and data D into three different levels and transmitting them by one data line. CONSTITUTION:A reset signal R is applied to an n type MOSTR7a, and if the input of the TR7a is in the high level, a data line 7h is turned to a power supply voltage level (6V). When a clock signal C is in the high level, an n type MOSTR7b is turned on, and when in the low level, the TR7b is turned off, so that the voltage of the data line 7h is changed between voltages 2V and 4V which are divided by resistors 7e-7g. If data D0-DF are in the high level, an n type MOSTR7c is turned on and the data line 7h is turned to the earth level. An LED displaying decoder driver part 8 receiving a signal on the data line 7h applies the input signal to three comparators 8a-8c, fixes respective comparison reference voltages by resistors 8c-8f and then extracts the reset signal, clock data from the outputs of the respective comparators.
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