Improved power efficiency in microprocessors by choosing the values of unused bits so as to minimise the Hamming distance between successive data values

摘要

A method of reducing the power consumption of a microprocessor system which comprises a microprocessor 2 and a memory 4 connected by a bus 6. The memory 4 contains a plurality of data values, each represented by a number of bits, for transmission to said microprocessor 2 via the bus 6 and at least some of said data values contain unused bits. The method includes assigning values to said unused bits in such a way as to reduce the Hamming distance between successive data values by a greater extent than setting all of said unused bits to an arbitrary predetermined value. Preferably each unused bit is replaced with the bit value of the corresponding bit from an adjacent data value.