| 摘要 |
PURPOSE:To simplify the constitution of a connection circuit which connects a magnetic card reader to a microcomputer by using the clock signal sent from the card reader as an interruption input signal and fetching the data from the card reader by the interruption processing. CONSTITUTION:When a magnetic card is put into a card reader, the card insertion signal CLS is changed to a level from a high level. Thus a microcomputer MCU is ready to read the card. Then a read clock pulse signal RCP is supplied to the MCU to produce an interruption NMI, and therefore only setting is performed for the flag data. Thus the procedure is reset to a main routine. In the main routine a card read data signal RDD is read when the flag data is set. The data is divided every 8 bits and transferred to an internal RAM of the MCU, and at the same time the flag data is reset. Then an interruption queuing state is set again. This operation is repeated to transfer all data to the RAM, and then the error checking is carried out.
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