| 摘要 |
PURPOSE:To reduce the capacity of an ROM and to simplify the constitution of a control circuit, by storing code length information and the inherent part of the code only to the ROM and outputting the complete code serially with externally mounted counter and selector only. CONSTITUTION:With an ROM4 ouputting an odd number of address, when a pulse for serial transmission is applied to a count-down input 13 of a down counter 5, although the down counter reduces the value at each one pulse, an output line 11 is positive when the preset value of the down counter is >=8, and a negative output is obtained until the down counter reaches 7 from the initial value being reduced. If the value of the down counter is <=7, a selector 6 sequentially outputs an ROM output 9 according to an address 12. The readout of one code and the output of serial conversion can be finished by applying a pulse to a count down input 13 until the value of the counter reaches 0 or a borrow 14 is obtained. |
