TRANSMISSION/RECEPTION DEVICE

摘要

PROBLEM TO BE SOLVED: To surely store digital data in a non-volatile memory even if power supply voltage decreases from a normal level in a configuration for storing digital data indicated by a data signal into the non-volatile memory when the data signal is received while power is fed by an external power signal. SOLUTION: A power supply circuit 12 generates a power supply voltage by a carrier signal received by a coil 8 for transponder. A microcomputer 3 stores digital data detected by a detection circuit 13 at an EEPROM 6. In this case, a CR oscillation circuit 14 reduces its oscillation frequency according to the reduction in power supply voltage so that the microcomputer 3 detects the power supply voltage based on the oscillation frequency of the CR oscillation circuit 14 and sets the unit write length of the EEPROM 6 to a short value and at the same time, gives the digital data of unit write length to the EEPROM 6 when the power supply voltage is lower than a normal level.