Clock servo

Clock servo

The flexPTP requires a clock servo to calculate how to tune the clock in steady state. A proper servo must define the following four functions:

1. A function that initializes the servo. No parameters are passed. (refer to PTP_SERVO_INIT())

1. A function that deinitializes the servo. No parameters are passed. (refer to PTP_SERVO_DEINIT())
2. A function that resets the servo. No parameters passed. (refer to PTP_SERVO_RESET())
3. A function that runs the servo. Two parameters passed: the time error in nanoseconds and the synchronization cycle context (as a pointer to a PtpServoAuxInput object). (refer to PTP_SERVO_RUN())

Clock servo functions must be passed to the flexPTP core by filling the servo-related macros in the flexptp_config.h configuration file.

Here we want to hightlight, that a servo init function is not constrained to only initialize the core of a controller. The developer is highly encouraged to include e.g. logging or debug functionality also in the controller.

Examples

A PID-controller based servo is bundled to the flexPTP package: pid_controller.c, pid_controller.h