Patent ID: 7711517

Claim:
A system for testing the accuracy of real time clocks, the system comprising a unit under test (UUT), the UUT comprising a real time clock (RTC) to be tested; the system further comprising a fixture and a database connected to the UUT, the fixture comprising an RTC integrated circuit (IC), a microcontroller, and a data converting chip, wherein the microcontroller connects with the RTC IC and the data converting chip through a multi-master serial computer bus, the data converting chip connects with the UUT through an external I/O serial bus; the microcontroller being configured for reading the initial time of the RTC IC, and sending the initial time to the data converting chip; the data converting chip being configured for converting the initial time of a format of the multi-master serial computer bus sent from the microcontroller to data of a format of the external I/O serial bus recognizable by the UUT, and sending the converted data to the UUT; the UUT further comprising a test program, the test program comprising: a parameters setting module being configured for setting test parameters for testing the accuracy of the RTC, and storing the test parameters in the database, the test parameters comprising a test time length, a test time sampling interval, and an acceptable margin for a time difference; a synchronizing module being configured for synchronizing the time of the RTC IC and the RTC when the test process has started; an obtaining module being configured for reading a current time of the RTC IC and the RTC at each test time sampling interval; and an analyzing module being configured for calculating a time difference between the current time of the RTC IC and the current time of the RTC, and determining whether the accuracy of the RTC is satisfactory by measuring whether the absolute value of the time difference is less than the acceptable margin within the test time length.