Output circuit and method that inverts the data byte if the number of changed bits compared with the last byte is more than half the total number of bits.

摘要

A data output circuit which outputs data received on an internal bus line onto an external bus line comprises a comparator, an inverter and a controller. The comparator compares data on the external bus line and data to be output received on the internal line. The inverter outputs the inverse of the data received on the internal bus when the number of bits that would be changed exceeds half the total number of bits in a byte and determined by the result output by the comparator. The controller outputs an inversion display signal indicating that the data has or has not been inverted. The circuit may be a control unit. The circuit may comprise an amplifier which amplifies the read data, data latch means for latching data from the amplifier and means for feeding the data to the comparator. The circuit may comprise a clock supply means to supply a clock signal to the data latch and/or the comparator. The control circuit may be arranged to control a plurality of groups, the groups obtained by classifying the internal bus lines into groups.