| 摘要 |
PURPOSE:To automatically set a transmission speed, to facilitate handling and to evade setting error by measuring the pulse width of a start bit of reception data at the time of staring transmission and temporarily setting the transmission speed of reception data based on the measured value to settle the transmission speed. CONSTITUTION:When the input level goes to the low level to confirm the start of the start bit pulse, period measurement of the start bit pulse is started by a period measuring circuit 14. The operation of the period measuring circuit 14 is terminated to give a measured period T to a clock generator 16. Parallel reception data Rx-Data is taken in from a serial-parallel converting circuit 10 and operations of the clock generator 16 and a counter 18 are stopped. Finally, coincidence between parallel data and preliminarily prescribed '0, 1, 0, 1, 0, 1, 0, 1' is checked, and the operation is terminated if coincidence is discriminated. Thus, the temporarily set transmission speed is settled and set as the actual transmission speed.
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