Method for processing noise interference in data accessing device with serial advanced technology attachment interface

This application claims the benefit of the filing date of Taiwan Application Ser. No. 093112284, filed on Apr. 30, 2004, the content of which is incorporated herein by reference.

1. Field of the Invention

The invention relates to a method for processing noise interference, and more particularly to a method for processing noise interference in a serial AT Attachment (SATA) interface according to the error condition in a receiver.

2. Description of the Related Art

The serial ATA (Serial Advanced Technology Attachment, hereinafter referred to as SATA) is an interface specification commonly promoted by the companies of APT, Dell, IBM, Intel, Maxtor, Seagate, etc. The SATA specification is applied to the transmission interface of a hard disk drive or an optical disk drive to replace parallel ATA/ATAPI interface that has been used for a long time. The SATA interface specification specifies two pairs of differential signal lines to replace the original 40 or 80 signal lines connected in parallel. Serializing the original data can reduce the size and voltage and increase the speed. The specification also introduces some new functions, such as flow control and error resending, to control the data stream in a simple way.

FIG. 1 is a schematic illustration showing communication layers in the SATA specification. As shown in FIG. 1 , the SATA interface connects a host 11 to a device 12 . The device 12 may be an optical storage device or a hard disk drive, or other devices with the SATA interface. The communication layers in the SATA specification include four layers, which are respectively a first layer (physical layer), a second layer (link layer), a third layer (transport layer) and a fourth layer (application layer). The physical layer is responsible for converting digital and analog signals. That is, the physical layer receives and converts a digital signal sent from the link layer into an analog signal and sends the analog signal to the other end. The physical layer also receives and converts the analog signal, which comes from the other end, into a digital signal and outputs the digital signal to the link layer. The link layer encodes and decodes the digital data. That is, the link layer encodes the data coming from the transport layer and outputs the encoded data to the physical layer. On the other hand, the link layer decodes the data coming from the physical layer and outputs the decoded data to the transport layer. The transport layer constructs and deconstructs the FIS (Frame Information Structure). The detailed definition of the FIS can be found in the SATA specification. The application layer is in charge of buffer memory and DMA engine(s).

During the serializing process, the sending device converts the parallel data (e.g., data in bytes or words) into a serial bit data stream. In addition to the typical data, the SATA specification defines some data control codes with four bytes, which are referred to as primitives, for controlling the sending and power management of the sending device and the receiving device. For example, a X_RDY primitive (transmission data ready primitive) represents that the sending device is ready to send the data, and a R_RDY primitive (receiver ready primitive) represents that the receiving device is ready to receive data.

FIG. 2 is a schematic illustration showing a packet sent through the SATA interface. Two devices communicate with each other to send the packet according to the X_RDY primitive (transmission data ready primitive) and the R_RDY primitive (receiver ready primitive). Then, the sending side sends a packet content, which is packed by a SOF primitive (start of frame) and an EOF primitive (End of frame). After the the packet content is sent completely, the sending side sends a WTRM primitive (wait for frame termination primitive). If there is no any error about the CRC (Cyclic Redundancy Check) check in the link, the receiving side responds with a R_OK primitive (reception with no error primitive) after it receives the WTRM primitive. If there is an error about the CRC check, the receiving side responds with R_ERR primitive (reception error).

In addition to the above-mentioned primitives, the specification further provides a HOLD primitive (hold data transmission primitive) and a HOLDA primitive (hold acknowledge primitive) for the flow control. The transmitter can output the HOLD primitive when it cannot transmit data temporarily, and the receiver responds with the HOLDA primitive. Alternatively, the receiver can output the HOLD primitive when it cannot receive the data, and the transmitter has to stop transmitting data and to transmit the HOLDA primitive so as to avoid data loss after it has received the HOLD primitive. FIG. 3 shows an example of using the HOLD primitive and the HOLDA primitive.

However, if the SOF primitive is interfered by the noise during the transmission such that the receiver cannot recognize the SOF primitive, the receiver continuously outputs the R_RDY Primitive. Hence, because the transmitter does not know that the receiver does not receive the SOF primitive, the transmitter transmits the rest of data until the WTRM primitive is sent. Because the receiver does not receive the SOF primitive, the receiver responds with a SYNC primitive (synchronization primitive) when the receiver receives the data. After the transmitter receives the synchronous primitive, the system will halt.

It is therefore an object of the invention to provide a method for processing noise interference, in which a receiver outputs a R_ERR primitive (receiving error primitive) to process the noise interference.

To achieve the above-mentioned object, the method of the invention for processing noise interference includes the steps of: enabling a receiver to output the R_RDY primitive after the X_RDY primitive is received; enabling the receiver to detect the EOF primitive and output the R_ERR primitive if the SOF primitive is not detected since it receives X_RDY primitive; and enabling the receiver to start to receive data after the SOF primitive is received.

FIG. 1 is a schematic illustration showing communication layers in the SATA specification.

FIG. 2 is a schematic illustration showing a FIS sent through the SATA interface.

FIG. 3 is another schematic illustration showing a FIS sent through the SATA interface.

FIG. 4 is a flow chart showing a method for processing noise interference according to a first embodiment of the invention, wherein a HOLD primitive is issued to process the noise interference.

FIG. 5 is a flow chart showing a method for processing noise interference according to a second embodiment of the invention, wherein a R_ERR primitive is issued to process the noise interference.

The invention will be described with reference to the accompanying drawings. FIG. 4 is a flow chart showing a method for processing the interference according to a first embodiment of the invention. The method for processing the interference utilizes a HOLD primitive to process the interference. FIG. 5 is a flow chart showing a method for processing interference according to a second embodiment of the invention. The method for processing the interference utilizes a R_ERR primitive to process the interference. The methods of the invention for processing the interference will be described with reference to FIGS. 4 and 5 .

Step S 402 is to detect whether the transport layer requests the data transmission. When the transport layer does not request the data transmission, the step is repeated. If the transport layer requests the data transmission, the procedure jumps to a next step (Step S 408 ).

Step S 408 is to output a X_RDY Primitive and to output a SOF primitive after a R_RDY primitive is received. Then, the procedure jumps to step S 410 .

Step S 410 is to check whether the data transmission is finished. If the data transmission is completed, the procedure jumps to step S 420 ; or otherwise the procedure jumps to step S 412 .

Step S 412 is to detect whether an error exists. The so-called error means the 8b/10b decoding error, the 8b/10b disparity error, that the received primitive cannot be recognized, or the physical layer error. When there is an error occurred, the procedure jumps to step S 416 ; or otherwise the procedure jumps to step S 414 .

Step S 414 is to output data and then the procedure jumps back to step S 410 .

Step S 416 is to output a HOLD primitive, and then the procedure jumps back to step S 410 .

Therefore, according to the above-mentioned steps, a HOLD primitive will be issued when the receiver has detected an error.

The operation flow of the receiver will be described with reference to FIG. 5 .

Step S 502 is to detect whether the device in the far end requests to transmit data. When the device in the far end does not request to transmit data, the step is repeated. If it requests the data transmission, the procedure jumps to a next step (Step S 506 ).

Step S 506 is to output a R_RDY primitive and then the procedure jumps to step S 508 .

Step S 508 is to detect whether the X_RDY primitive exists. If the X_RDY primitive is detected, the procedure jumps back to step S 506 ; or otherwise the procedure jumps to step S 510 .

Step S 510 is to detect whether the SOF primitive exists. If the SOF primitive is detected, the procedure jumps to step S 516 ; or otherwise the procedure jumps to step S 512 .

Step S 512 is to detect whether an EOF primitive or a WTRM primitive exists. If any of the two primitives is detected, the procedure jumps to step S 514 ; or otherwise the procedure jumps back to step S 506 .

Step S 514 is to output a R_ERR primitive, and then the procedure jumps to step S 530 .

Step S 516 is to detect whether an EOF primitive or a WTRM primitive exists. If one of the two primitives is detected, the procedure jumps to step S 518 . If both of the two primitives are not detected, the procedure jumps to step S 520 .

Step S 518 is to output a R_OK primitive or a R_ERR primitive, and then the procedure jumps to step S 530 . If the CRC value calculated according to the received data is not equal to the CRC value transmitted from the other side, the R_ERR primitive is outputted, or otherwise the R_OK primitive is outputted.

Step S 520 is to detect whether there is an error. The so-called error means that the 8b/10b decoding error, the decoding/disparity error, or the physical layer error. When there is an error occurred, the procedure jumps to step S 524 ; or otherwise the procedure jumps to step S 522 .

Step S 522 is to output a R_IP primitive (reception in progress primitive) and then the procedure jumps back to step S 516 .

Step S 524 is to output a HOLD primitive and then the procedure jumps back to step S 516 .

According to the above-mentioned steps, when the receiver receives an EOF primitive or a WTRM primitive before the SOF primitive is received, it represents that the SOF primitive is interfered by the noise and cannot be recognized by the receiver. So, the receiver outputs the R_ERR primitive after it receives the EOF primitive or the WTRM primitive. Thus, the transmitter resends data after it receives the R_ERR primitive. It is possible to avoid the dead lock condition between the receiver and the transmitter, and the function of avoiding errors may be achieved.

While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific construction and arrangement shown and described, since various other modifications may occur to those ordinarily skilled in the art.