1) Created MSTP_Create_And_Send_Frame function.

2) Moved MSTP_Create_Frame call out of rs485.c and into mstp.c
3) Modified all previous calls to RS485_Send_Frame calls to call
MSTP_Create_And_Send_Frame instead.

bacnet-stack/rs485.h

@@ -41,11 +41,8 @@
 
 void RS485_Send_Frame(
   struct mstp_port_struct_t *mstp_port, // port specific data
-  uint8_t frame_type, // type of frame to send - see defines
-  uint8_t destination, // destination address
-  uint8_t source,  // source address
-  uint8_t *data, // any data to be sent - may be null
-  unsigned data_len); // number of bytes of data (up to 501)
+  uint8_t *buffer, // frame to send (up to 501 bytes of data)
+  uint16_t nbytes); // number of bytes of data (up to 501)
 
 void RS485_Check_UART_Data(
   struct mstp_port_struct_t *mstp_port); // port specific data