Added missing MS/TP zero configuration preferred address API and usage. (#840)

ports/stm32f4xx/main.c

@@ -98,9 +98,11 @@ int main(void)
     MSTP_Port.InputBufferSize = sizeof(Input_Buffer);
     MSTP_Port.OutputBuffer = Output_Buffer;
     MSTP_Port.OutputBufferSize = sizeof(Output_Buffer);
-    /* user data */
+    /* choose from non-volatile configuration for zero-config or slave mode */
     MSTP_Port.ZeroConfigEnabled = true;
+    MSTP_Port.Zero_Config_Preferred_Station = 0;
     MSTP_Port.SlaveNodeEnabled = false;
+    /* user data */
     MSTP_User_Data.RS485_Driver = &RS485_Driver;
     MSTP_Port.UserData = &MSTP_User_Data;
     dlmstp_init((char *)&MSTP_Port);

src/bacnet/datalink/dlmstp.c

@@ -611,6 +611,116 @@ void dlmstp_get_broadcast_address(BACNET_ADDRESS *dest)
     return;
 }
 
+/**
+ * @brief Get the MSTP port SoleMaster status
+ * @return true if the MSTP port is the SoleMaster
+ */
+bool dlmstp_sole_master(void)
+{
+    if (!MSTP_Port) {
+        return false;
+    }
+    if (MSTP_Port->SoleMaster) {
+        return true;
+    }
+
+    return false;
+}
+
+/**
+ * @brief Get the MSTP port SlaveNodeEnabled status
+ * @return true if the MSTP port has SlaveNodeEnabled
+ */
+bool dlmstp_slave_mode_enabled(void)
+{
+    if (!MSTP_Port) {
+        return false;
+    }
+    return MSTP_Port->SlaveNodeEnabled;
+}
+
+/**
+ * @brief Set the MSTP port SlaveNodeEnabled flag
+ * @param flag - true if the MSTP port has SlaveNodeEnabled
+ * @return true if the MSTP port SlaveNodeEnabled was set
+ * @note This flag is used to enable the Slave Node state machine
+ * for the MSTP port.  The Slave Node state machine is used to
+ * respond to requests from the Master Node.
+ */
+bool dlmstp_slave_mode_enabled_set(bool flag)
+{
+    if (!MSTP_Port) {
+        return false;
+    }
+    MSTP_Port->SlaveNodeEnabled = flag;
+
+    return true;
+}
+
+/**
+ * @brief Get the MSTP port ZeroConfigEnabled status
+ * @return true if the MSTP port has ZeroConfigEnabled
+ */
+bool dlmstp_zero_config_enabled(void)
+{
+    if (!MSTP_Port) {
+        return false;
+    }
+    return MSTP_Port->ZeroConfigEnabled;
+}
+
+/**
+ * @brief Set the MSTP port ZeroConfigEnabled flag
+ * @param flag - true if the MSTP port has ZeroConfigEnabled
+ * @return true if the MSTP port ZeroConfigEnabled was set
+ * @note This flag is used to enable the Zero Configuration state machine
+ * for the MSTP port.  The Zero Configuration state machine is used to
+ * automatically assign a MAC address to the MSTP port.
+ */
+bool dlmstp_zero_config_enabled_set(bool flag)
+{
+    if (!MSTP_Port) {
+        return false;
+    }
+    MSTP_Port->ZeroConfigEnabled = flag;
+
+    return true;
+}
+
+/**
+ * @brief Get the MSTP port MAC address that this node prefers to use.
+ * @return ZeroConfigStation value
+ */
+uint8_t dlmstp_zero_config_preferred_station(void)
+{
+    if (!MSTP_Port) {
+        return Nmin_poll_station;
+    }
+    if ((MSTP_Port->Zero_Config_Preferred_Station < Nmin_poll_station) ||
+        (MSTP_Port->Zero_Config_Preferred_Station > Nmax_poll_station)) {
+        return Nmin_poll_station;
+    }
+
+    return MSTP_Port->Zero_Config_Preferred_Station;
+}
+
+/**
+ * @brief Set the MSTP port MAC address that this node prefers to use.
+ * @param station - Zero_Config_Preferred_Station value
+ * @return true if the MSTP port Zero_Config_Preferred_Station was set
+ */
+bool dlmstp_zero_config_preferred_station_set(uint8_t station)
+{
+    if (!MSTP_Port) {
+        return false;
+    }
+    /* note: valid values are between Nmin_poll_station and Nmax_poll_station
+       but other values such as 0 or 255 could mean 'unconfigured' */
+    MSTP_Port->Zero_Config_Preferred_Station = station;
+
+    return true;
+}
+
 /**
  * @brief Determine if the send PDU queue is empty
  * @return true if the send PDU is empty

src/bacnet/datalink/dlmstp.h

@@ -179,6 +179,20 @@ void dlmstp_fill_bacnet_address(BACNET_ADDRESS *src, uint8_t mstp_address);
 
 BACNET_STACK_EXPORT
 bool dlmstp_sole_master(void);
+BACNET_STACK_EXPORT
+bool dlmstp_slave_mode_enabled(void);
+BACNET_STACK_EXPORT
+bool dlmstp_slave_mode_enabled_set(bool flag);
+
+BACNET_STACK_EXPORT
+bool dlmstp_zero_config_enabled(void);
+BACNET_STACK_EXPORT
+bool dlmstp_zero_config_enabled_set(bool flag);
+BACNET_STACK_EXPORT
+uint8_t dlmstp_zero_config_preferred_station(void);
+BACNET_STACK_EXPORT
+bool dlmstp_zero_config_preferred_station_set(uint8_t station);
+
 BACNET_STACK_EXPORT
 bool dlmstp_send_pdu_queue_empty(void);
 BACNET_STACK_EXPORT

src/bacnet/datalink/mstp.c

@@ -1403,7 +1403,12 @@ static void MSTP_Zero_Config_State_Init(struct mstp_port_struct_t *mstp_port)
         return;
     }
     mstp_port->Poll_Count = 0;
-    mstp_port->Zero_Config_Station = Nmin_poll_station;
+    /* initialize the zero config station address */
+    if ((mstp_port->Zero_Config_Preferred_Station < Nmin_poll_station) ||
+        (mstp_port->Zero_Config_Preferred_Station > Nmax_poll_station)) {
+        mstp_port->Zero_Config_Preferred_Station = Nmin_poll_station;
+    }
+    mstp_port->Zero_Config_Station = mstp_port->Zero_Config_Preferred_Station;
     mstp_port->Npoll_slot = 1 + (mstp_port->UUID[0] % Nmax_poll_slot);
     /* basic silence timeout is the dropped token time plus
         one Tslot after the last master node. Add one Tslot of

src/bacnet/datalink/mstp.h

@@ -164,6 +164,8 @@ struct mstp_port_struct_t {
     /* the MAC address that this node is testing for MAC addresses
        that are not in-use.*/
     uint8_t Zero_Config_Station;
+    /* the MAC address that this node prefers to use.*/
+    uint8_t Zero_Config_Preferred_Station;
     /* Used to count the number of received poll-for-master frames
        This is used in the detection of addresses not in-use. */
     uint8_t Poll_Count;