Patent ID: 6911843

Claim:
A data transfer device, comprising: a high speed operating unit for receiving input serial data in a data receiving operation in synchronization with a first clock signal having a frequency corresponding to a high transmission speed, converting the input serial data into reception parallel data, and transmitting output serial data in a data transmitting operation in synchronization with the first clock signal; and a low speed operating unit for receiving the reception parallel data transferred from the high speed operating unit in synchronization with a second clock signal having a frequency lower than that of the first clock signal and transferring transmission parallel data to the high speed operating unit in synchronization with the second clock signal, wherein the high speed operating unit comprises: a count signal producing unit for circularly counting the number of pulses of the first clock signal in a count range corresponding to a prescribed clock cycle, and producing a plurality of count signals indicating count values currently obtained so as to include both a first count signal indicating a first count value and a second count signal indicating a second count value; a clock signal producing unit for producing the second clock signal by forming a first edge of each pulse in response to the first count signal produced by the count signal producing unit in synchronization with the first clock signal and forming a second edge of each pulse in response to the second count signal produced by the count signal producing unit in synchronization with the first clock signal, and transmitting the second clock signal to the low speed operating unit; and a data converting unit for receiving the input serial data in synchronization with the first clock signal in the serial data receiving operation, converting the input serial data into the reception parallel data in synchronization with the first clock signal, driving the reception parallel data in response to one of the count signals produced by the count signal producing unit so as to sample the reception parallel data in the low speed operating unit in synchronization with the second clock signal, sampling the transmission parallel data, which is driven by the low speed operating unit in synchronization with the second clock signal in the serial data transmitting operation, in response to one of the count signals produced by the count signal producing unit, converting the transmission parallel data into the output serial data in synchronization with the first clock signal, and transmitting the output serial data in synchronization with the first clock signal.