For design methodology of CRC or cyclic redundancy check is very used technique for error checking and shows the transmission reliability we are using the HDLC block. HDLC block is very useful in data communication these block operated in data link layer. For design methodology of CRC is to generate the CRC polynomial using XOR’s gate and shift register these polynomial are implement on software Xilinx Plan Ahead 13.1 and verify for simulation result for random testing of CRC bit on receiver side same result are obtained to show that it is more reliable.

1. International Journal of Scientific Research Engineering & Technology (IJSRET)
Volume 2 Issue 5 pp 242-246 August 2013 www.ijsret.org ISSN 2278 – 0882
IJSRET @ 2013
Performance Evaluation & Design Methodologies for Automated 32 Bit
CRC Checking for 32 bit address Using HDLC Block
Neeraj Kumar Misra,
(Assistant professor, Dept. of ECE, R D Foundation Group of Institution Ghaziabad, India
Email: neeraj.mishra3@gmail.com)
ABSTRACT
For design methodology of CRC or cyclic redundancy
check is very used technique for error checking and
shows the transmission reliability we are using the
HDLC block. HDLC block is very useful in data
communication these block operated in data link layer.
For design methodology of CRC is to generate the
CRC polynomial using XOR’s gate and shift register
these polynomial are implement on software Xilinx
Plan Ahead 13.1 and verify for simulation result for
random testing of CRC bit on receiver side same result
are obtained to show that it is more reliable.
Keywords – CRC, XILINX, HDLC, LFSR, OSI
I. INTRODUCTION
In OSI model first layer is physical layer. This layer
takes care of getting data on the wire and off of it
again. At the data link layer, we must take this
incoming stream of data from higher or lower layers
and create frames from it. Handling the data requires a
solid protocol that can perform better error checking
and more efficient throughputs. That data is performed
by HDLC block. Basically ISO termed it as High level
Data Link Control (HDLC).HDLC has own standard
frame format. In the framing of HDLC one block is
CRC [Cyclic Redundancy Checking] it is basically
error checking number that the Destination can use to
verify that the packet is error free. This is usually done
by the data link protocol and calculated CRC is
appended to the end of the data link layer frame.
II. LITERATURE SURVEY
Main focus of the survey is to understand the data link
layer and develop a protocol which can offer its
services to the layer above it i.e. is the network layer
and the layer below it i.e. the physical layer. Function
of this protocol controller is to perform a number of
separate activities like physical addressing, to check for
errors, flow control etc.
Fig a. Network Layer Interaction
III. COMPETITIVE OVERVIEW OF CRC
AND HDLC BLOCK
In HDLC overview HDLC device contains a full-
duplex transceiver with independent transmit and
receive sections for bit-level HDLC protocol
operations. The core is designed for easy integration
into wide range of applications implemented on most
ASIC’s and FPGA’s technologies. Now the controllers
generate and detect flags that indicate the HDLC status.
They provide 32-bit CRC on data packets using defined
polynomial, and recognize the single byte address in
the received frame.
Fig b. Transmit Section of HDLC

2. International Journal of Scientific Research Engineering & Technology (IJSRET)
Volume 2 Issue 5 pp 242-246 August 2013 www.ijsret.org ISSN 2278 – 0882
IJSRET @ 2013
Fig c. Receiver section of HDLC
In transmitting and receiving section of HDLC the
packet data are serially, while providing the data
transparency through zero insertion and deletion. These
controllers generate and detect flags that indicate the
HDLC status. They provide 32-bit CRC on data
packets using the CRC defined polynomial, and
recognize the single byte address in the received frame.
CRC 32bit Polynomial [32 bits] = X32 + X26
+ X23 + X22 + X16 + X12 + X11 + X10 + X8
+ X7 + X5 + X4 + X2 + X + 1 HEX CODE
04C11DB7
In CRC overview it is powerful method for detecting
errors in the received data is by grouping the bytes of
data into a block and calculating a Cyclic Redundancy
Check (CRC). This is usually done by the data link
protocol and calculated CRC is appended to the end of
the data link layer frame. The CRC is calculated by
performing a modulo 2 division of the data by a
generator polynomial and recording the remainder after
division
Fig d. Modular division of CRC
IV. SOFTWARE APPROACH INTENTION
OF MODULAR DIVISION OF CRC
Division may be performed in software, it usually
performed using a shift register and X-OR gates. The
hardware solution for implementing a CRC is much
simpler than a software approach. For example for a
CRC-32bit is:
Fig e. Software approach of CRC generation
Depending upon the data of the MSB register in the
Linear Feedback shift register (LFSR), shifting and
XOR operations occur. This serial LFSR
implementation is converted into a one shot or single
cycle operation. Now this approach is converted into
polynomial that is CRC polynomial. Suppose
polynomial x3
+x+1 is generated the generated circuit
for CRC is shown fig e.
Fig f. CRC GENERATOR CIRCUIT
V. DESIGN METHODOLOGIES OF CRC
USING HDLC BLOCK
A practical implementation of a decoder also requires a
method to initialize the encoder prior to transmission of
the first bit of data in a frame, and to flush the encoder
after sending the last byte. In the example below (which
uses a different representation of the schematics for X-
OR gates and shift register elements), the process starts
by initializing the encoder with zero bits, by setting the
switch to B. Some CRC's initialize the register to a non-

3. International Journal of Scientific Research Engineering & Technology (IJSRET)
Volume 2 Issue 5 pp 242-246 August 2013 www.ijsret.org ISSN 2278 – 0882
IJSRET @ 2013
zero value, which can give added detection capability
when the first set of bits in a frame may themselves be
zero. Then the switch is moved to position A and one
data bit enter the encoder for each clock cycle. The data
bits are immediately available at the output. After the last
bit has been sent, the switch is returned to position B and
the contents of the encoder are sent to the output. This is
often called flushing the encoder and requires one clock
cycle per bit held in the shift register.
On reception, the process is reversed. The CRC register
is first set to zero (or the initial value on transmission, if
non-zero). The bits (this time including the CRC) are fed
into the register on each clock cycle. If the CRC contains
the value zero (assuming initialization was zero), the
CRC is valid, if not it has detected an error. The CRC-32
is able to detect all single errors, all double errors, all
odd numbers of errors and all errors with burst less than
32 bits in length. In addition 99.9984 % of other error
patterns will be detected. Protocols at the network layer
and higher (e.g. IP, UDP, TCP) usually use a simpler
checksum to verify that the data being transported has
not been corrupted by the processing performed by the
nodes in the network.
Fig g. Implementation of encoder and decoder
Fig h. Design Methodology of 32Bit CRC
After the packet with the polynomial the remainder comes
out to be zero that means the transmission and reception are
error free and in case the remainder is not zero that means
an error has occurred during the process and hence the
packet is discarded and the whole packet is retransmitted.
Fig i. CRC Checking Method
VI. SOFTWARE USED PARAMETER OF
CRC
Initially, the digital design (block diagram) will be
drafted showing the basic functioning of the hardware
Change the Polynomial to a divisor of size N+1
Make a shift register of size N
Align the shift register cells with the divisor so
that the cells are located between the bits
Put a XOR gate where there is a 1 in the divisor
except for the leftmost bit
Make a feedback connection from the leftmost
bit to the XORs.

4. International Journal of Scientific Research Engineering & Technology (IJSRET)
Volume 2 Issue 5 pp 242-246 August 2013 www.ijsret.org ISSN 2278 – 0882
IJSRET @ 2013
in terms of the blocks. This will then be coded in a
hardware description language (VHDL). The
functioning of the coded design is to be simulated on
simulation software (e.g. ModelSim). After proper
simulation, the design is to be synthesized and then
translated to a structural architecture in terms of the
components on the target FPGA device (Spartan 3) and
the perform the post-translate simulation in order to
ensure the proper functioning of the design after
translation.
CRC Parameter taken
data<=11110000
16bitaddress
txaddressinlo<=11110000,
txaddressinhi<=11110000,
txadrressout<=1111000011110000
clock=1,reset=0,
wrtaddresshi=1
wrtaddresslo=1.
VII. PERFORMANCE EVALUATION OF
CRC CHECKING
CRC parameter taken to simulate the simulation
software modelsim after the address and the data are
attached together, we divide them with a constant
polynomial of 32 bits and append the remainder of the
division along the data and address.
Fig j. Simulation result for CRC at transmit section
In this simulation coded in Xilinx software transmitter
crc32 bit is 11000110011………that crc 32 bit is
verified in same in receiver obtained a
crc32<=0000000000000000000000000000000 which
indicates an error free transmission and simulation
result is shown below
Fig k. Simulation result for CRC at receiver section

5. International Journal of Scientific Research Engineering & Technology (IJSRET)
Volume 2 Issue 5 pp 242-246 August 2013 www.ijsret.org ISSN 2278 – 0882
IJSRET @ 2013
VIII. FUTURE IMPROVEMENT
Design methodology of CRC is checking properly
using HDLC block. The main agenda is HDLC it
improve performance of HDLC like it more features
can be added to increase its utility. There are several
modifications, which can further improve its
performance. These are listed below-
It can be further enhanced to256 Independent, Bi-
directional HDLC Channels, Large 16kB FIFO in Both
Receive and Transmit Directions and Transmit Packet
Priority Setting.
IX. CONCLUSION
This paper explains an easy and efficient method of
generating automated CRC generations for
synthesizable use software Xilinx Plan Ahead 13.1.
The check frame sequence generation using cyclic
redundancy checks CRC-32 to ensure error free
transmission.
REFERENCE
Journal Papers:
[1] Neeraj Mishra, “ Xilinx HDLC Controller
Supporting IP over SONET AND Calculation of 16, 32
Bit CRC for 8,16 bit address” International Conference
on Communications & Electronics 19th – 20th
October, 2012
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