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Description
The Phase-II upgrade of the China Spallation Neutron Source (CSNS-II), aiming for a 500-kW beam power, imposes stringent physical constraints on beam synchronization, necessitating a paradigm shift from conventional static triggers to physics-driven accelerator control. This paper presents the development and field implementation of an innovative MicroTCA.4-based global timing system for the CSNS-II Rapid Cycling Synchrotron (RCS). During the phase-locked injection, the Medium Energy Beam Transport (MEBT) chopper is modulated precisely by the RCS Radio Frequency (RF) sweep sequence, truncating the irregular transient edges of the ion source macro-pulse to sculpt an optimal beam time structure. Upon arrival, the linac beam is alternately injected into two RCS RF buckets at the synchronous phase for optimal capture. Importantly, the timing system anchors this microscopic injection epoch to the macroscopic valley of the main resonant magnet waveform. This rigorous spatiotemporal alignment ensures precise matching between the injection kinetic energy and the dipole bending strength, thereby preventing closed-orbit distortions and emittance dilution. Following a 20-ms synchronous acceleration, the system executes a dynamic extraction sequence, orchestrating eight independent kicker magnets to achieve a flawless, single-turn extraction of two high-intensity proton bunches. To address the complex multidimensional synchronization challenges, the proposed architecture integrates event and synchronous timing schemes on a highly deterministic System-on-Chip (SoC) FPGA platform. By providing unified, sub-nanosecond coordination for both Low-Level RF (LLRF) and Beam Instrumentation (BI) subsystems, this beam-adaptive architecture has been validated through field operations, establishing a robust synchronization foundation for megawatt-class accelerator facilities.