Patent ID: 7949809

Claim:
A PCI express interface, including a down data channel for transmitting data from media access control layer to physical media access layer via physical coding sub-layer, wherein said down data channel comprises: input interface unit for sampling with the clock of corresponding frequency according to the bit number of the received data transmitted from media access control layer to physical coding sub-layer, converting the data in the data format of media access control layer into the data to be coded conforming to the data format of physical coding sub-layer, sampling received data polarity control signal which controls the data polarity and data identity signal which indicates transmission type under the clock of physical coding sub-layer and outputting; and coding unit for receiving the data to be coded, data identity signal and data polarity control signal outputted from input interface unit and the data polarity signal which is provided by physical coding sub-layer indicating the data polarity, coding the data to be coded according to the data polarity signal after controlled by the data polarity control signal, and determining whether to transmit the coded data to physical media access layer according to the data identity signal; and wherein when received data is of 8 bits, the input interface unit samples data with the clock of 125 MHz frequency and outputs; and when received data is of 16 bits, it samples data with the clock of 250 MHz frequency and outputs.