7 Startup and Shutdown Synchronization

When shutting down or restarting a multiphase system, the phases need to remain synchronized. The gating of the PWM outputs is achieved using the PWM’s override feature. The state of the PWM outputs is configurable in override. In this example, both PWMxH and PWMxL are driven to logic ‘0’. Given that there are 12 PGs, each with its own control register, software cannot write all the override enables at the same time for concurrent control of all 24 outputs. To achieve synchronized operation, the override synchronization feature is used. The override enable bits OVRENH and OVRENL are buffered like the PWM data registers. The override state is applied with a request and can be applied to all client PGs at one time. This allows the stop and start of all PWM outputs in a single PWM cycle, at the end of the cycle. PG1 and APG1 are the hosts and broadcast the override update signal to the rest of the PGs as override clients.