Data access device and method for communication system

A data access device for a communication system, said data access device downloading data from a host and transmitting data to a network interface, said data access device comprising:

• a write controller being controlled by the host and outputting a write pointer;
• a read controller being controlled by the write pointer and outputting a read pointer;
• a download timing controller comparing the write pointer and the read pointer to determine a timing of downloading data from the host, said download timing controller including a pointer difference calculator and a comparator, said pointer difference calculator calculating a distance between the write pointer and the read pointer to obtain a pointer difference, said comparator outputting a download status indication according to the pointer difference and a first predetermined length in order to provide a basis for changing the write pointer;
• and
• a transmit buffer downloading data from the host according to the write pointer and transmitting data to the network interface according to the read pointer,
• wherein said download timing controller further includes a predetermined length calculator adding a predetermined retransmit length and a predetermined guard band length to obtain the first predetermined length.

A data access method for a communication system to be implemented by a data access device including a transmit buffer, the transmit buffer downloading data according to a write pointer and transmitting data according to a read pointer, said data access method comprising:

• calculating a distance between the write pointer and the read pointer to obtain a pointer difference, wherein the read pointer is outputted by a read controller being controlled by the write pointer;
• generating a download status indication according to the pointer difference and a first predetermined length;
• and
• changing the write pointer according to the download status indication,
• wherein the first predetermined length is equal to a predetermined retransmit length.

A data access method for a communication system to be implemented by a data access device including a transmit buffer, the transmit buffer downloading data according to a write pointer and transmitting data according to a read pointer, said data access method comprising:

• calculating a distance between the write pointer and the read pointer to obtain a pointer difference, wherein the read pointer is outputted by a read controller being controlled by the write pointer;
• generating a download status indication according to the pointer difference and a first predetermined length;
• and
• changing the write pointer according to the download status indication,
• wherein the first predetermined length is equal to a sum of a predetermined retransmit length and a predetermined guard band length.

A data access device for a network interface controller, said data access device transmitting data stored in a host to a network interface, said data access device comprising:

• a write controller determining a write pointer according to a control signal output by the host;
• a read controller determining a read pointer according to the write pointer;
• a download timing controller determining whether to receive data from the host according to the read pointer and the write pointer, said download timing controller including
• a pointer difference calculator calculating a distance between the write pointer and the read pointer to obtain a pointer difference, and
• a comparator outputting an indication according to the pointer difference and a predetermined length in order to instruct said data access device whether or not to receive data from the host;
• and
• a first-in-first-out (FIFO) buffer receiving data from the host according to the write pointer and transmitting data to the network interface according to the read pointer,
• wherein said download timing controller uses a predetermined retransmit length as the first predetermined length.

A data access device for a network interface controller, said data access device transmitting data stored in a host to a network interface, said data access device comprising:

• a write controller determining a write pointer according to a control signal output by the host;
• a read controller determining a read pointer according to the write pointer;
• a download timing controller determining whether to receive data from the host according to the read pointer and the write pointer, said download timing controller including
• a pointer difference calculator calculating a distance between the write pointer and the read pointer to obtain a pointer difference, and
• a comparator outputting an indication according to the pointer difference and a predetermined length in order to instruct said data access device whether or not to receive data from the host;
• and
• a first-in-first-out (FIFO) buffer receiving data from the host according to the write pointer and transmitting data to the network interface according to the read pointer,
• wherein said download timing controller further includes a predetermined length calculator adding a predetermined retransmit length and a predetermined guard band length to obtain the first predetermined length.