WRITE ENABLE CIRCUIT, ACCESS SWITCH CIRCUIT, AND ANALOG/DIGITAL CONVERSION UNIT

摘要

Provided is a write enable circuit which outputs a write enable signal of digital data which has been analog/digital converted, in an analog/digital conversion unit comprising a bus control unit which is connected to an external unit, a computation processing unit which carries out data processing, and a computation unit which retains the digital data which has been analog/digital converted, said analog/digital conversion unit having a regular access mode in which the digital data is written to the bus control unit after being initially written to the computation processing unit and a fast access mode in which the digital data is written directly to the bus control unit. The write enable circuit comprises: an address match determination circuit which is provided in the computation unit and, if a predetermined address in the memory of the bus control unit matches an address which the computation processing unit has designated, outputs the write enable signal from the computation unit; and a logic circuit which receives the input of the write enable signal in the bus control unit only if the computation processing unit has asserted a fast access signal which signifies the fast access mode.