In recent years semiconductor memories, such as radio frequency (RF) tags, having a radio communication function have increased in number. RF tags which perform radio communication in an ultra-high frequency (UHF) band are being standardized by EPCglobal (registered trademark) and are used for commodity tags and the like. Furthermore, RF tags to which an image display device, such as electronic paper, is connected are also known.
Formerly data received by an RF tag are temporarily held in a volatile storage circuit (hereinafter referred to as a volatile buffer) before the data are written to a nonvolatile memory. If en error is not detected in the data, then the data are written to the nonvolatile memory. For example, a memory write packet prescribed by the EPCglobal standard includes a cyclic redundancy check (CRC) value for error detection in addition to a command and data. A control circuit in an RF tag performs error detection on data held in a volatile buffer by the use of a CRC value. If an error is detected, then a retransmission request is made. If an error is not detected, then the data held in the volatile buffer are written to a nonvolatile memory.
Japanese Laid-open Patent Publication No. 2010-286935
Japanese Laid-open Patent Publication No. 2015-60409
However, if a semiconductor memory having a radio communication function receives not only data, such as setting information, whose data amount is comparatively small but also data, such as image data, whose data amount is comparatively large, then the storage capacity of a volatile buffer corresponds to a large data amount. As a result, data whose data amount is large are written to or read out from the volatile buffer. This increases power consumption.