Added a check for a new byte when moving back to IDLE for MS/TP capture utility.

bacnet-stack/demo/mstpcap/main.c

@@ -71,6 +71,8 @@
 static volatile struct mstp_port_struct_t MSTP_Port;
 /* track the receive state to know when there is a broken packet */
 static MSTP_RECEIVE_STATE MSTP_Receive_State = MSTP_RECEIVE_STATE_IDLE;
+/* track the bytes that are incoming to know when to check for loss */
+static bool DataAvailable;
 /* buffers needed by mstp port struct */
 static uint8_t RxBuffer[MAX_MPDU];
 static uint8_t TxBuffer[MAX_MPDU];
@@ -1174,6 +1176,7 @@ int main(
     /* run forever */
     for (;;) {
         RS485_Check_UART_Data(mstp_port);
+        DataAvailable = mstp_port->DataAvailable;
         MSTP_Receive_Frame_FSM(mstp_port);
         /* process the data portion of the frame */
         if (mstp_port->ReceivedValidFrame) {
@@ -1192,7 +1195,8 @@ int main(
             mstp_structure_init(mstp_port);
             Invalid_Frame_Count++;
             packet_count++;
-        } else if (mstp_port->receive_state == MSTP_RECEIVE_STATE_IDLE) {
+        } else if ((mstp_port->receive_state == MSTP_RECEIVE_STATE_IDLE) &&
+                (DataAvailable)) {
             if (MSTP_Receive_State == MSTP_RECEIVE_STATE_IDLE) {
                 if (mstp_port->EventCount) {
                     write_received_packet(mstp_port, 1);