Added MS/TP automatic baudrate detection option into the core MS/TP state machine. (#900)

src/bacnet/datalink/dlmstp.c

@@ -417,7 +417,7 @@ uint16_t dlmstp_receive(
             MSTP_Slave_Node_FSM(MSTP_Port);
         } else if (
             (MSTP_Port->This_Station <= DEFAULT_MAX_MASTER) ||
-            MSTP_Port->ZeroConfigEnabled) {
+            MSTP_Port->ZeroConfigEnabled || MSTP_Port->CheckAutoBaud) {
             while (MSTP_Master_Node_FSM(MSTP_Port)) {
                 /* do nothing while some states fast transition */
             };
@@ -700,6 +700,39 @@ bool dlmstp_zero_config_enabled_set(bool flag)
     return true;
 }
 
+/**
+ * @brief Get the MSTP port AutoBaudEnabled status
+ * @return true if the MSTP port has AutoBaudEnabled
+ */
+bool dlmstp_check_auto_baud(void)
+{
+    if (!MSTP_Port) {
+        return false;
+    }
+    return MSTP_Port->CheckAutoBaud;
+}
+
+/**
+ * @brief Set the MSTP port AutoBaudEnabled flag
+ * @param flag - true if the MSTP port has AutoBaudEnabled
+ * @return true if the MSTP port AutoBaudEnabled 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_check_auto_baud_set(bool flag)
+{
+    if (!MSTP_Port) {
+        return false;
+    }
+    MSTP_Port->CheckAutoBaud = flag;
+    if (flag) {
+        MSTP_Port->Auto_Baud_State = MSTP_AUTO_BAUD_STATE_INIT;
+    }
+
+    return true;
+}
+
 /**
  * @brief Get the MSTP port MAC address that this node prefers to use.
  * @return ZeroConfigStation value, or an out-of-range value if invalid
@@ -961,6 +994,46 @@ uint32_t dlmstp_silence_milliseconds(void *arg)
     return milliseconds;
 }
 
+/**
+ * @brief Return the valid frame time in milliseconds
+ * @param arg - pointer to MSTP port structure
+ * @return valid frame time in milliseconds
+ */
+uint32_t dlmstp_valid_frame_milliseconds(void *arg)
+{
+    uint32_t milliseconds = 0, now = 0;
+    struct mstp_port_struct_t *port = arg;
+    struct dlmstp_user_data_t *user = NULL;
+
+    if (port) {
+        user = port->UserData;
+    }
+    if (user) {
+        now = mstimer_now();
+        milliseconds = now - user->Valid_Frame_Milliseconds;
+    }
+
+    return milliseconds;
+}
+
+/**
+ * @brief Reset the valid frame timer
+ * @param arg - pointer to MSTP port structure
+ * @return valid frame time in milliseconds
+ */
+void dlmstp_valid_frame_milliseconds_reset(void *arg)
+{
+    struct mstp_port_struct_t *port = arg;
+    struct dlmstp_user_data_t *user = NULL;
+
+    if (port) {
+        user = port->UserData;
+    }
+    if (user) {
+        user->Valid_Frame_Milliseconds = mstimer_now();
+    }
+}
+
 /**
  * @brief Reset the RS-485 silence time to zero
  * @param arg - pointer to MSTP port structure
@@ -994,6 +1067,10 @@ bool dlmstp_init(char *ifname)
     if (MSTP_Port) {
         MSTP_Port->SilenceTimer = dlmstp_silence_milliseconds;
         MSTP_Port->SilenceTimerReset = dlmstp_silence_reset;
+        MSTP_Port->ValidFrameTimer = dlmstp_valid_frame_milliseconds;
+        MSTP_Port->ValidFrameTimerReset = dlmstp_valid_frame_milliseconds_reset;
+        MSTP_Port->BaudRate = dlmstp_baud_rate;
+        MSTP_Port->BaudRateSet = dlmstp_set_baud_rate;
         user = (struct dlmstp_user_data_t *)MSTP_Port->UserData;
         if (user && !user->Initialized) {
             Ringbuf_Initialize(