Corrected number of FSM cycles and related description

components/ulp/include/esp32/ulp.h

@@ -900,13 +900,12 @@ esp_err_t ulp_run(uint32_t entry_point);
  *
  * @param period_index wakeup period setting number (0 - 4)
  * @param period_us wakeup period, us
- * @note  The ULP FSM requires some time to wakeup before being able to run the program.
- *        Then additional time is reserved after wakeup waiting until the 8M clock is stable.
- *        The FSM also requires time to go to sleep after the program execution is halted.
+ * @note  The ULP FSM requires two clock cycles to wakeup before being able to run the program.
+ *        Then additional 16 cycles are reserved after wakeup waiting until the 8M clock is stable.
+ *        The FSM also requires two more clock cycles to go to sleep after the program execution is halted.
  *        The minimum wakeup period that may be set up for the ULP
- *        is the total time spent on the above internal tasks.
- *        For a default configuration of the ULP running at 150kHz
- *        the minimum wakeup period is about 160us.
+ *        is equal to the total number of cycles spent on the above internal tasks.
+ *        For a default configuration of the ULP running at 150kHz it makes about 133us.
  * @return
  *      - ESP_OK on success
  *      - ESP_ERR_INVALID_ARG if period_index is out of range