Backplane testing system and method thereof

A backplane testing method, which comprising the following steps:

• providing a backplane and a backplane testing system, wherein the backplane includes a plurality of SAS ports, a first positive differential signal circuit and a first negative differential signal circuit, the backplane testing system includes a loop device and a core testing device, the loop device includes a plurality of dummy SAS units, the plurality of dummy SAS units are electrically connected to the plurality of SAS ports one-to-one, each of the plurality of dummy SAS unit is configured to receive a differential signal or a test signal, which conforms to IEEE-1149.6 boundary scan test standard, from the corresponding SAS port, and sends the differential signal or the test signal back to the corresponding SAS port, the core testing device includes a control module, a differential signal transceiver, and a JTAG interface, the JTAG interface is connected to the loop device, the control module is connected to the JTAG interface, the differential signal transceiver is connected to the control module, the differential signal transceiver includes a second positive differential signal circuit and a second negative differential signal circuit, the first positive differential signal circuit is connected to the second positive differential signal circuit and one of the plurality of SAS ports, the first negative differential signal circuit connects the second negative differential signal circuit and another of the plurality of SAS ports;
• controlling, by the control module, the plurality of dummy SAS units in parallel through the JTAG interface;
• sending, by the control module, the a first control command to the differential signal transceiver;
• when the differential signal transceiver receiving the first control command and generating a set of PRBS as the differential signal, the differential signal transceiver sending the differential signal to the backplane through the second positive differential signal circuit and the second negative differential signal circuit, and receiving the returned differential signal based on connection relationship and signal transmission relationship of the differential signal transceiver, the backplane and the loop device, and determining whether the differential signal sent and the differential signal received are the same;
• sending, by the control module, a second control command to the differential signal transceiver;
• and
• when the differential signal transceiver receiving the second control command and generating the test signal that conforming to the IEEE-1149.6 boundary scan test standard, the differential signal transceiver sending the test signal through the second positive differential signal circuit and the second negative differential signal circuit respectively, and receiving the returned test signal through the second positive differential signal circuit and the second negative differential signal circuit based on the connection relationship and the signal transmission relationship of the differential signal transceiver, the backplane and the loop device respectively, and determining whether the test signal sent and the test signal received through the second positive differential signal circuit are the same and whether the test signal sent and the test signal received through the second negative differential signal circuit are the same.