HDLC PROTOCOL CONTROLLER FOR SENSOR DATA PROCESSING

AIM:  To model and design an efficient sensor data processing system.  Provides ease of integration with other technologies and techniques like I.Packet based data communication II.Data buffering management III.Data security& compression IV.Rf based wireless communication

TRANSMITTING UNIT MULTI SENSOR DATA MULTIPLEXER A/D CONVERTOR ENCODING AND SENDING MODULE

RECEIVING UNIT RECEIVING AND DECODING MODULE D/A CONVERTOR DE MULTIPLEXER RECEIVER

DESIGN AND IMPLEMENTATION OF HDLC PROCEDURES  High level data link control procedures  Established by international organization for standardization(ISO)  Widely used in digital communications  HDLC procedures are bit oriented  More flexible  More efficient  Basic transfer unit is a frame.

HDLC FRAME STRUCTURE  Flag is 8 bit field  Address is an 8 bit field  Control is an 8 bit field  Info or data is an 8 bit field  CRC is a frame check sequence and uses16/32 bit.

 The first field is for frame synchronization flag and is ‘ ’ for both header and frame end.  The second is address of the receiving station.  The third field is a control code  The fourth field is the information and is a multiple of 8 bits.  The fifth field is Frame Check Sequence.

HDLC MODULES DESIGN

ENCODING-AND-SENDING MODULE:  Adopts finite state machine in VHDL consisting of five stages:  Idle state  Frame header sending state  User data sending state  CRC codes sending state  Frame end sending state

RECEIVING-AND-DECODING MODULE  Adopts finite state machine and consists of  Frame header detecting state  User data processing state  CRC verifying and comparing state  Storage flag generation state  Data storing state

APPLICATIONS:  Sensor data processing in fields like I.mineral processing II.Patient monitoring III.Sensor data instrumentation IV.Bio medical instrumentation V.Radar sensor data processing

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