2.11 Serial Interface Circuit
Fig. 13 Serial Interface Circuit Diagram
RS-232 is an asynchronous transfer interface, which used with externally connected
personal computer and keyboard unit. JP15 connects to PC serial interface through the
RS-232 cable. RxD is a data receive pin of MCU. CTS is clear to send of MCU, which
sends a signal from the external device. TxD is a data output pin of MCU. RTS is the
request to send signal, which sends signal to the external device.
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