Ethercat解析（十三）之fsm_master状态机

1. fsm_master结构体

struct ec_fsm_master {
    ec_master_t *master; /**< master the FSM runs on */
    ec_datagram_t *datagram; /**< datagram used in the state machine */
    unsigned int retries; /**< retries on datagram timeout. */

    void (*state)(ec_fsm_master_t *); /**< master state function */
    ec_device_index_t dev_idx; /**< Current device index (for scanning etc.).
                            */
    int idle; /**< state machine is in idle phase */
    unsigned long scan_jiffies; /**< beginning of slave scanning */
    uint8_t link_state[EC_MAX_NUM_DEVICES]; /**< Last link state for every
                                          device. */
    unsigned int slaves_responding[EC_MAX_NUM_DEVICES]; /**< Number of
                                                      responding slaves
                                                      for every device. */
    unsigned int rescan_required; /**< A bus rescan is required. */
    ec_slave_state_t slave_states[EC_MAX_NUM_DEVICES]; /**< AL states of
                                                     responding slaves for
                                                     every device. */
    ec_slave_t *slave; /**< current slave */
    ec_sii_write_request_t *sii_request; /**< SII write request */
    off_t sii_index; /**< index to SII write request data */
    ec_sdo_request_t *sdo_request; /**< SDO request to process. */

    ec_fsm_coe_t fsm_coe; /**< CoE state machine */
    ec_fsm_soe_t fsm_soe; /**< SoE state machine */
    ec_fsm_pdo_t fsm_pdo; /**< PDO configuration state machine. */
    ec_fsm_change_t fsm_change; /**< State change state machine */
    ec_fsm_slave_config_t fsm_slave_config; /**< slave state machine */
    ec_fsm_slave_scan_t fsm_slave_scan; /**< slave state machine */
    ec_fsm_sii_t fsm_sii; /**< SII state machine */
};

2.函数调用关系

以IDLE为例，状态机周期调用关系如下图所示：

其中ec_master_idle_thread()的调用周期与系统滴答时间有关：

//send interval in IDLE phase
ec_master_set_send_interval(master, 1000000/HZ);