The present invention provides a data memory controller that supports for the invert of data bus. Data transmitted from a memory is received in a chip set, which further transmits the data to a data processing apparatus. While receiving the memory data, the chip set doubles the bandwidth and reduces the frequency, such that the time margin for processing data is increased. In addition, after outputting data to the data processing apparatus, a first frame of data is compared to bus idle state to further reduce frequency of data invert and power consumption.