Pulse-based synchronization training for synchronous digital and mixed-signal systems
Systems and methods for synchronizing the clocks of a central device and one or more destination devices are disclosed. In some embodiments the central device and destination devices are implemented in a space-based or high-altitude asset. The central device provides a series of synchronization pulses to the one or more destination devices. In response to detecting, at the destination device, the synchronization pulse, a sample of the destination device clock is stored in a register. The sample is provided to the central device. The sequence is repeated at least once. A phase offset between the central device clock and the destination device clock may be determined based on the returned samples and the position of the samples within the register.
1. A method of synchronizing clock signals in a system implemented in a space-based or high-altitude asset, the system comprising a central device having a central device clock and a destination device having a destination device clock, the method comprising:
(a) obtaining a first delay amount;
(b) providing, by the central device, a pulse signal to the destination device, wherein the pulse signal is advanced or retarded by the delay amount;
(c) detecting, at the destination device, the pulse signal;
(d) in response to detecting the pulse signal, obtaining, at the destination device, a sample of the destination device clock and storing the sample in a register;
(e) providing the sample of the destination device clock to the central device;
(f) determining, by the central device, whether enough samples are stored in the register to enable calculation of a phase offset between the central device clock and the destination device clock, wherein the phase offset may be calculated when an edge of the destination device clock is detected based on the samples;
(g) in accordance with a determination that a phase offset cannot be calculated, adjusting the first delay amount and repeating steps (a)-(f); and
(h) in accordance with a determination that the phase offset can be calculated, then calculating, by the central device, the phase offset based on a position, in the register, of the sample representing the edge of the destination device clock.