| 摘要 |
<p>PURPOSE:To prevent erroneous write by preliminarily detecting presence/absence of voltage abnormality in a data carrier to store this detection data and preventing execution of the write processing to output a write response indicating the voltage abnormality in the case of an abnormal voltage. CONSTITUTION:When a data carrier 4 is approximated to a read/write head 3 and power is supplied, it is checked by a power discriminating means whether the supply voltage is normal or not, and the check result is stored as a status signal in a status storage means. When a write command is inputted to an ID controller 2 from, for example, a higher controller 1, the ID controller 2 immediately sends the write command to the memory of the data carrier 4 and checks the status signal sent from the data carrier 4 before the write processing. If the status signal indicates the voltage abnormality, the write response indicating that the supply voltage is abnormal is outputted to the higher controller 2 without performing the write processing. Thus, the write processing is performed only when the voltage is normal.</p> |
