Dynamic Block Reed-Solomon Decoder User’s Guide
December 2010
IPUG52_01.6
Table of Contents
Chapter 1. Introduction .......................................................................................................................... 4
Quick Facts ........................................................................................................................................................... 4
Features ................................................................................................................................................................ 8
Chapter 2. Functional Description ...................................................................................................... 10
Block Diagram..................................................................................................................................................... 10
General Description ............................................................................................................................................ 10
Field Polynomial......................................................................................................................................... 11
Generator Polynomial ................................................................................................................................ 11
Shortened Codes ....................................................................................................................................... 11
Systematic Decoder ................................................................................................................................... 11
Decoding Modes ........................................................................................................................................ 11
Functional Description......................................................................................................................................... 12
Syndrome Transform ................................................................................................................................. 13
Key Equation Solver................................................................................................................................... 13
Error Locator .............................................................................................................................................. 13
Error Magnitude Corrector ......................................................................................................................... 13
Control Unit ................................................................................................................................................ 13
Basis Conversion Modules......................................................................................................................... 13
Variable Block Size .................................................................................................................................... 13
Variable Check Symbols ............................................................................................................................ 14
Puncturing Pattern File Format ........................................................................................................................... 14
Default Field Polynomials........................................................................................................................... 14
Signal Descriptions ............................................................................................................................................. 15
Timing Specifications .......................................................................................................................................... 17
Chapter 3. Parameter Settings ............................................................................................................ 20
RS Decoder Configuration GUI........................................................................................................................... 21
Core Configuration ..................................................................................................................................... 21
RS Parameters........................................................................................................................................... 21
Check Symbols .......................................................................................................................................... 22
Block Size Type ......................................................................................................................................... 22
Puncturing .................................................................................................................................................. 22
Decoding Mode .......................................................................................................................................... 22
Memory Type ............................................................................................................................................. 22
Optional Ports ............................................................................................................................................ 23
Chapter 4. IP Core Generation............................................................................................................. 24
Licensing the IP Core.......................................................................................................................................... 24
Getting Started .................................................................................................................................................... 24
IPexpress-Created Files and Top Level Directory Structure............................................................................... 26
Instantiating the Core .......................................................................................................................................... 28
Running Functional Simulation ........................................................................................................................... 28
Synthesizing and Implementing the Core in a Top-Level Design ....................................................................... 28
Hardware Evaluation........................................................................................................................................... 29
Enabling Hardware Evaluation in Diamond................................................................................................ 29
Enabling Hardware Evaluation in ispLEVER.............................................................................................. 29
Updating/Regenerating the IP Core .................................................................................................................... 29
Regenerating an IP Core in Diamond ........................................................................................................ 29
Regenerating an IP Core in ispLEVER ...................................................................................................... 30
Chapter 5. Support Resources ............................................................................................................ 31
Lattice Technical Support.................................................................................................................................... 31
© 2010 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand
or product names are trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
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Dynamic Block Reed-Solomon Decoder User’s Guide
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Table of Contents
Online Forums............................................................................................................................................ 31
Telephone Support Hotline ........................................................................................................................ 31
E-mail Support ........................................................................................................................................... 31
Local Support ............................................................................................................................................. 31
Internet ....................................................................................................................................................... 31
References.......................................................................................................................................................... 31
LatticeEC/ECP ........................................................................................................................................... 31
LatticeECP2M ............................................................................................................................................ 31
LatticeECP3 ............................................................................................................................................... 31
LatticeSC/M................................................................................................................................................ 32
LatticeXP.................................................................................................................................................... 32
LatticeXP2.................................................................................................................................................. 32
Related Information............................................................................................................................................. 32
Revision History .................................................................................................................................................. 32
Appendix A. Resource Utilization ....................................................................................................... 33
LatticeECP and LatticeEC FPGAs ...................................................................................................................... 34
Ordering Part Number................................................................................................................................ 34
LatticeECP2 and LatticeECP2S FPGAs ............................................................................................................. 34
Ordering Part Number................................................................................................................................ 34
LatticeECP2M and LatticeECP2MS FPGAs ....................................................................................................... 35
Ordering Part Number................................................................................................................................ 35
LatticeECP3 FPGAs............................................................................................................................................ 35
Ordering Part Number................................................................................................................................ 35
LatticeXP FPGAs ................................................................................................................................................ 36
Ordering Part Number................................................................................................................................ 36
LatticeXP2 FPGAs .............................................................................................................................................. 36
Ordering Part Number................................................................................................................................ 36
LatticeSC and LatticeSCM FPGAs ..................................................................................................................... 37
Ordering Part Number................................................................................................................................ 37
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3
Dynamic Block Reed-Solomon Decoder User’s Guide
Chapter 1:
Introduction
Reed-Solomon codes are widely used in various communications and storage applications for forward error correction. Reed-Solomon codes are well suited for burst error correction and are frequently used as outer codes in communication systems. A Reed-Solomon Decoder performs detection and correction of the encoded data at the
receiver. Lattice’s Dynamic Block Reed-Solomon Decoder (RS Decoder) IP core is compliant with several industry
standards including the more recent IEEE 802.16-2004 and can be custom configured to support other non-standard applications as well. The RS Decoder supports a wide range of symbol widths and allows the user to define
the field polynomial, generator polynomial and several other parameters.
The newer standards like IEEE 802.16-2004 require the use of Reed-Solomon codes with dynamically varying
block sizes. Lattice’s RS Decoder IP core provides an ideal solution that meets such needs of today’s forward error
correction world. This core allows the block size and number of check symbols to be varied dynamically through
input ports. Lattice’s RS Decoder IP can be used with Lattice’s RS Decoder for a complete Reed-Solomon code
based forward error correction application. For more information on these and other IP products for forward error
correction, refer to the Lattice web site at www.latticesemi.com/products/intellectualproperty.
Quick Facts
Table 1-1 through Table 1-9 give quick facts about the RS Decoder IP core for LatticeEC™, LatticeECP™,
LattceECP2™, LattticeSC™, LatticeSCM™, LatticeXP™, LatticeECP2M™, LatticeXP2™, and LatticeECP3™
devices.
Table 1-1. RS Decoder IP core for LatticeEC Devices Quick Facts
RS Decoder IP Configuration
OC-192
Core
Requirements
CCSDS
Minimal Device Needed
LUTs
sysMEM EBRs
Registers
LFEC1E
LFEC3E
Synthesis
LFEC3E
LFEC3E
LFEC3E
1100
2000
1200
1500
1900
2100
2
2
2
2
3
3
900
1500
900
1100
1400
1600
®
Lattice Diamond™ 1.0 or ispLEVER 8.1
Synopsys® Synplify™ Pro for Lattice D-2009.12L-1
Aldec® Active-HDL™ 8.2 Lattice Edition
Simulation
IPUG52_01.6, December 2010
LFEC1E
LFEC20E-5F672C
Lattice Implementation
Design Tool
Support
ATSC
IEEE
802.162004 SC
LatticeEC
Targeted Device
Resource
Utilization
DVB
FPGA Families Supported
IEEE 802.162004
SCa/OFDM
Mentor Graphics® ModelSim™ SE 6.3F
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Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Introduction
Table 1-2. RS Decoder IP core for LatticeECP Devices Quick Facts
RS Decoder IP Configuration
OC-192
Core
Requirements
CCSDS
LUTs
sysMEM EBRs
IEEE
802.162004 SC
LatticeECP
Minimal Device Needed
Registers
LFECP6E
LFECP20E-5F672C
1100
2000
1200
1500
1900
2100
2
2
2
2
3
3
900
1500
900
1100
1400
1600
Lattice Implementation
Design Tool
Support
ATSC
FPGA Families Supported
Targeted Device
Resource
Utilization
DVB
IEEE 802.162004
SCa/OFDM
Lattice Diamond 1.0 or ispLEVER 8.1
Synthesis
Synopsys Synplify Pro for Lattice D-2009.12L-1
Aldec Active-HDL 8.2 Lattice Edition
Simulation
Mentor Graphics ModelSim SE 6.3F
Table 1-3. RS Decoder IP core for LatticeECP2 Devices Quick Facts
RS Decoder IP Configuration
OC-192
Core
Requirements
CCSDS
FPGA Families Supported
Minimal Device Needed
LUTs
sysMEM EBRs
Registers
LFE2-6E
LFE2-50E-7F672C
1100
2000
1200
1500
1800
2100
2
2
2
2
3
3
900
1500
900
1100
1400
1600
Lattice Implementation
Design Tool
Support
ATSC
Synthesis
Lattice Diamond 1.0 or ispLEVER 8.1
Synopsys Synplify Pro for Lattice D-2009.12L-1
Aldec Active-HDL 8.2 Lattice Edition
Simulation
IPUG52_01.6, December 2010
IEEE
802.162004 SC
LatticeECP2
Targeted Device
Resource
Utilization
DVB
IEEE 802.162004
SCa/OFDM
Mentor Graphics ModelSim SE 6.3F
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Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Introduction
Table 1-4. RS Decoder IP core for LatticeSC Devices Quick Facts
RS Decoder IP Configuration
OC-192
Core
Requirements
CCSDS
FPGA Families Supported
LUTs
sysMEM EBRs
Registers
1900
2200
LFSC3GA15E
LFSC3GA25E-7F900C
1200
2000
1200
1600
2
2
2
2
3
3
900
1500
900
1000
1400
1600
Lattice Implementation
Design Tool
Support
ATSC
IEEE
802.162004 SC
LatticeSC
Minimal Device Needed
Targeted Device
Resource
Utilization
DVB
IEEE 802.162004
SCa/OFDM
Lattice Diamond 1.0 or ispLEVER 8.1
Synthesis
Synopsys Synplify Pro for Lattice D-2009.12L-1
Aldec Active-HDL 8.2 Lattice Edition
Simulation
Mentor Graphics ModelSim SE 6.3F
Table 1-5. RS Decoder IP core for LatticeSCM Devices Quick Facts
RS Decoder IP Configuration
OC-192
Core
Requirements
CCSDS
FPGA Families Supported
LUTs
sysMEM EBRs
Registers
LFSCM3GA15EP1
LFSCM3GA25EP1-7F900C
1200
2000
Synthesis
1600
1900
2200
2
2
2
2
3
3
1500
900
1000
1400
1600
Lattice Diamond 1.0 or ispLEVER 8.1
Synopsys Synplify Pro for Lattice D-2009.12L-1
Aldec Active-HDL 8.2 Lattice Edition
Simulation
IPUG52_01.6, December 2010
1200
900
Lattice Implementation
Design Tool
Support
ATSC
IEEE
802.162004 SC
Lattice SCM
Minimal Device Needed
Targeted Device
Resource
Utilization
DVB
IEEE 802.162004
SCa/OFDM
Mentor Graphics ModelSim SE 6.3F
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Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Introduction
Table 1-6. RS Decoder IP core for LatticeXP Devices Quick Facts
RS Decoder IP Configuration
OC-192
Core
Requirements
CCSDS
LUTs
sysMEM EBRs
IEEE
802.162004 SC
1900
2100
Lattice XP
Minimal Device Needed
Registers
LFXP3E
LFXP20E-5F484C
1100
2000
1200
1500
2
2
2
2
3
3
900
1500
900
1100
1400
1600
Lattice Implementation
Design Tool
Support
ATSC
FPGA Families Supported
Targeted Device
Resource
Utilization
DVB
IEEE 802.162004
SCa/OFDM
Lattice Diamond 1.0 or ispLEVER 8.1
Synthesis
Synopsys Synplify Pro for Lattice D-2009.12L-1
Aldec Active-HDL 8.2 Lattice Edition
Simulation
Mentor Graphics ModelSim SE 6.3F
Table 1-7. RS Decoder IP core for LatticeECP2M Devices Quick Facts
RS Decoderr IP Configuration
OC-192
Core
Requirements
CCSDS
FPGA Families Supported
LUTs
sysMEM EBRs
Registers
Synthesis
2100
LFE2M35E-7F484C
1100
2000
1200
1500
2
2
2
2
3
3
900
1500
900
1100
1400
1600
Lattice Diamond 1.0 or ispLEVER 8.1
Synopsys Synplify Pro for Lattice D-2009.12L-1
Aldec Active-HDL 8.2 Lattice Edition
Simulation
IPUG52_01.6, December 2010
1800
LFE2M20E
Lattice Implementation
Design Tool
Support
ATSC
IEEE
802.162004 SC
Lattice ECP2M
Minimal Device Needed
Targeted Device
Resource
Utilization
DVB
IEEE 802.162004
SCa/OFDM
Mentor Graphics ModelSim SE 6.3F
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Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Introduction
Table 1-8. RS Decoder IP core for LatticeXP2 Devices Quick Facts
RS Decoder IP Configuration
OC-192
Core
Requirements
CCSDS
DVB
FPGA Families Supported
Lattice XP2
Minimal Device Needed
LFXP2-5E
Targeted Device
Resource
Utilization
LUTs
sysMEM EBRs
Registers
IEEE
802.162004 SC
LFXP2-17E-7FT256C
1100
2000
1200
1500
1800
2100
2
2
2
2
3
3
900
1500
900
1100
1400
1600
Lattice Implementation
Design Tool
Support
ATSC
IEEE 802.162004
SCa/OFDM
Lattice Diamond 1.0 or ispLEVER 8.1
Synthesis
Synopsys Synplify Pro for Lattice D-2009.12L-1
Aldec Active-HDL 8.2 Lattice Edition
Simulation
Mentor Graphics ModelSim SE 6.3F
Table 1-9. RS Decoder IP core for LatticeECP3 Devices Quick Facts
RS Decoder IP Configuration
OC-192
Core
Requirements
CCSDS
FPGA Families Supported
LUTs
sysMEM EBRs
Registers
Synthesis
1800
2100
LFE3-35EA
LFE3-95E-8FN672CES
1100
2000
1200
1500
2
2
2
2
3
3
900
1500
900
1100
1400
1600
Lattice Implementation
Design Tool
Support
ATSC
IEEE
802.162004 SC
Lattice ECP3
Minimal Device Needed
Targeted Device
Resource
Utilization
DVB
IEEE 802.162004
SCa/OFDM
Lattice Diamond 1.0 or ispLEVER 8.1
Synopsys Synplify Pro for Lattice D-2009.12L-1
Aldec Active-HDL 8.2 Lattice Edition
Simulation
Mentor Graphics ModelSim SE 6.3F
Features
• 3- to 12-Bit Symbol Width
• Configurable Field Polynomial
• Configurable Generator Polynomial: Starting Root and Root Spacing
• User-defined Codewords
– Maximum of 4095 symbols
– Maximum of 256 check symbols
– Shortened codes
• Off-the-shelf Support for the Following Communication Standards:
– OC-192
– DVB
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Dynamic Block Reed-Solomon Decoder User’s Guide
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–
–
–
–
Introduction
CCSDS
ATSC
IEEE 802.16-2004 WirelessMAN-SCa/OFDM
IEEE 802.16-2004 WirelessMAN-SC
• Fully Synchronous
• Systematic Decoder
• Full Handshaking Capability
• Dynamically Variable Block Size
• Dynamically Variable Check Symbols
• Error, Erasure and Puncturing Modes
• Error Measurement Information
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9
Dynamic Block Reed-Solomon Decoder User’s Guide
Chapter 2:
Functional Description
A block diagram of the RS Decoder is shown in Figure 2-1. The RS Decoder IP is comprised of the Syndrome
Transform, Key Equation Solver, Error Locator, Error Magnitude Corrector, Data Memory and Output Processing
blocks.
Block Diagram
Figure 2-1. RS Decoder Block Diagram
Control Bus
Error
Magnitude
Corrector
Syndrome
Transform
din
Key
Equation
Solver
Error
Locator
Output
Processing
Unit
dout
ddel
Data
Memory
clk
rstn
ibstart
ce
sr
ers
blocksize
obstart
obend
outvalid
errfnd
Control
rfi
rfib
fail
numchks
puncsel
errcnt
erscnt
General Description
Reed-Solomon codes are used to perform Forward Error Correction (FEC). FEC introduces controlled redundancy
in the data before it is transmitted to allow error correction at the receiver. The redundant data (check symbols) are
transmitted with the original data to the receiver. An RS Decoder is used in the receiver to correct any transmission
errors. This type of error correction is widely used in data communications applications such as Digital Video
Broadcasting (DVB) and Optical Carriers (i.e. OC-192).
Reed-Solomon codes are written in the format RS(n,k) where k is the number of information symbols and n is the
total number of symbols in a codeword or block. Each symbol in the codeword is wsymb bits wide. The RS Decoder
performs detection and correction of encoded data available at the receiver after demodulation. The RS encoded
data is then processed to determine whether any errors have occurred during transmission. Once the number of
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10 Dynamic Block Reed-Solomon Decoder User’s Guide
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Functional Description
errors is determined, the decoder decides if they are within the range of correction. After determining this, the
decoder corrects the errors in the received data. A typical application of space signal processing is shown in
Figure 2-2.
Figure 2-2. Application of Reed-Solomon Code in a Space Communication System
Input Data
RS Encoder
Interleaver
Convolutional
Encoder
Decoded Data
RS Decoder
Deinterleaver
Viterbi
Decoder
Transmitted Data
Received Data
Reed-Solomon codes are defined on a finite field known as Galois field. The size of the field is determined by the
symbol width, wsymb, and is equal to 2wsymb. When n is less than its maximum value of 2wsymb-1, the corresponding code RS(n,k) is referred to as a shortened code.
Reed-Solomon codes are characterized by two polynomials: the generator polynomial and the field polynomial.
The field polynomial defines the Galois field where the information and check symbols belong. The generator polynomial determines the check symbol generation and it is a prime polynomial for all codewords (i.e. all codewords
are exactly divisible by the generator polynomial). Both the field and the generator polynomials are user configurable.
Field Polynomial
The field polynomial is defined by its decimal value (f). The decimal value of a field polynomial is obtained by setting x = 2 in the polynomial. For example, the polynomial x2 + x + 1 in decimal value is 22 + 2 + 1 = 7. The field polynomial can be specified as any prime polynomial with decimal value up to 2wsymb+1 - 1.
Generator Polynomial
The generator polynomial determines the value of the check symbols. The generator polynomial can be defined by
the parameters starting root (gstart) and root spacing (rootspace). The general form of the generator polynomial is given by:
g(x) = (x - rootspace
n-k-1
i=0
(gstart + i))
(1)
where is called the primitive element of the field polynomial. For a binary Galois field GF(2), is equal to 2.
Shortened Codes
When the size of the Reed-Solomon codewords, n, is less than the maximum possible size, 2wsymb-1, they are called
shortened codes. For example, RS (204,188) when wsymb = 8 is a shortened code.
Systematic Decoder
The decoder can only decode data encoded by a systematic Reed-Solomon Encoder. In a systematic encoder, the
information symbols are unchanged and are followed by check symbols in the output.
Decoding Modes
The decoder can support Error, Erasure and Puncturing modes. In the error mode no information is available about
the symbols in error. In this mode the decoder needs to compute both position and magnitude of the error symbols.
In the erasure mode the user can dynamically indicate the erased symbols using the input port ers. Erased symbols are those symbols in error whose positions are known in advance. Error mode can be thought of a special
case of Erasure mode, when number of erased symbols is zero. Therefore it is not necessary to identify all correctable errors as erasures through the input port ers in the erasure mode and combinations of errors and erasures
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11 Dynamic Block Reed-Solomon Decoder User’s Guide
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Functional Description
can be used. If erased symbols are known and the position of the erased symbols can be dynamically indicated
using ers, then erasure mode is useful. The symbol correction capability of the decoder increases since the position of the symbol in error is already known and only the magnitude needs to be computed. Generally erasure support substantially increases the decoder latency and resource utilization. Puncturing mode is an optimized version
of the erasure mode and can be used when the position of the erased symbols is known in advance. The user can
define a maximum of (n - k) puncture patterns and can dynamically select one of these patterns using the input
port puncsel. The format for the puncture pattern file is explained in a later section. The decoder will be able to
correct the errors and erasures successfully if the following conditions are satisfied.
For the Error mode, the number of correctable errors Eerr is given by
Eerr = (n - k) /2, when Block size type is constant.
Eerr = (Number of check symbols) /2, when Block size type is variable and Variable check
symbols is not defined.
Eerr = (value on numchks port) /2, when Variable check symbols is defined.
For the Erasure and Puncturing modes, the number of correctable errors Eerr and the number of correctable erasures Eers (given through the input port ers) are bound by the following relations
(2 * Eerr + Eers ð (n - k)) and (Eers ((n - k - 2)), when Block size type is constant.
(2 * Eerr + Eers ð (Number of check symbols)) and (Eers ð (Number of check symbols - 2)), when
Block size type is variable.
Functional Description
A block diagram of the RS Decoder is shown in Figure 2-1. The RS Decoder is comprised of the Syndrome Transform, Key Equation Solver, Error Locator, Error Magnitude Corrector, Data Memory and Output Processing blocks.
The data received by the RS Decoder is Reed-Solomon encoded data. This data is a representation of a polynomial in a Galois Field. If there are no errors in the received data, the data polynomial will evaluate to zero at the
roots of the generator polynomial. This result is obtained because the roots of the generator polynomial and the
received data polynomial are the same when there are no errors. If the received data has been corrupted during
the transmission, the polynomial will not evaluate to zero. The RS Decoder can construct the syndrome polynomial
by evaluating the received polynomial at all the roots of the generator polynomial. Once the syndrome polynomial
has been constructed, it can be used to solve the Error Locator polynomial and Error Evaluator polynomial. Using
these two polynomials, the decoder can find the error locations and magnitudes. Finally, the decoder can correct
the errors in the received data, provided the errors are in the range of correctable errors (determined by the level of
encoding that has been performed).
If there are errors in the received codeword, it can be expressed as follows:
r(x) = c(x) + e(x)
where:
c(x) is the Transmitted codeword
r(x) is the Received codeword
e(x) is the Error polynomial
The syndrome polynomial S(x) is obtained by evaluating the received word at each root of the generator polynomial. The Error Locator polynomial (x) is orthogonal to the syndrome polynomial in the Galois field. This can be
represented as:
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12 Dynamic Block Reed-Solomon Decoder User’s Guide
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Functional Description
S(x)(x) = ¾(x) mod x2t
where:
¾(x) is the Error Evaluator polynomial.
2t is the number of check symbols introduced in the encoder.
The following sections describe the function of each block of the RS Decoder.
Syndrome Transform
The Syndrome Transform (also called Syndrome Generation) block evaluates the received codeword of the generator polynomial. If the received data contains an error, the syndrome polynomial generated will be non-zero. If the
received data has no error, the syndrome polynomial is zero, and the data is passed out of the decoder without any
error correction.
Key Equation Solver
This is the heart of the RS Decoder. This block generates the Error Locator polynomial (x) (also known as the
“Key Equation” as it is the key to solve the decoding problem). After the Error Locator polynomial has been determined, it is used to compute the Error Evaluator polynomial ¾(x)
Error Locator
This block is implemented using the Chien-search method. Essentially, this method evaluates the Error Locator
polynomial at all the elements in the Galois Field. The Error Locator polynomial evaluates to zero at its roots. The
Chien-search takes up to m cycles, where m is the number of elements in the Galois Field, to determine all the
roots. If the roots are determined before m cycles are over, the search is terminated early.
Error Magnitude Corrector
Once the location of the error has been determined, the Error Magnitude Corrector evaluates the evaluator polynomial at that root. It uses the result to calculate the value of the error at the given location. Once this has been determined, the value is added to the received word to recover the original data. The addition occurs only when the Error
Locator polynomial evaluates to zero.
Control Unit
The control unit handles the interface, pipelining and handshaking communication between the various blocks and
the I/O ports. The control circuit moves the data without processing it through the decoder when no error is
detected. Similarly, when the number of errors exceeds the maximum range of correction, the control circuit stops
all data processing activities. The control circuit interacts with the other blocks to generate the status signals like
obstart, obend, outvalid, rfib, errfnd, errcnt, erscnt and fail. Once the block has been processed,
the control circuit sends out the rfi signal to the output to start the processing of the next data block.
Basis Conversion Modules
When core configuration is selected as CCSDS, then two additional Basis Conversion modules are added to the
RS Decoder. These modules comply with the CCSDS specification. Dual-basis to normal polynomial-basis conversion module is added after the din input port and normal polynomial-basis to dual-basis conversion module is
added before the dout output port.
Variable Block Size
In the constant Block size type option, the block size value and number of information symbols are provided
as constant values through the RS Decoder GUI before core generation. For variable Block size type option,
the block size value is provided dynamically through the input port blocksize. The number of the information
symbols is calculated from the block size value provided through the input port and the number of check symbols.
The number of check symbols can be either constant and defined in the GUI or variable and given through the
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13 Dynamic Block Reed-Solomon Decoder User’s Guide
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Functional Description
input port numchks, depending on the parameter Variable check symbols. Once block size value, number of check
symbols and number of information symbols are known then the core operates in the same way as when block size
was constant.
Variable Check Symbols
This option can be used when there is requirement for variable error correction capability. One example of this type
of application is IEEE 802.16-2004 WirelessMAN-SC. In this option the number of check symbols value is provided
dynamically through the input port numchks. Dynamically Variable check symbols option is available only for
the Error Decoding mode.
Puncturing Pattern File Format
This file contains the pre-defined puncture patterns that are selected using the puncsel signal. This file is necessary when Decoding mode is selected as Puncturing. This file should have the “.cfg” extension. The RS Decoder
IP core GUI requires this file during core configuration. The format and a sample of this file is given below, followed
by a brief explanation.
Format:
....
First line lists the number of punctured symbols in each pattern. N is the total
number of puncture patterns. There should be N lines following this line, one for
each pattern
....
...
...
These are the actual puncture patterns. Each line contains one pattern. p1, p2,
etc. in each pattern are the positions of the punctured symbols from the end of the
block for that pattern.
...
...
The number of punctured symbols in the first line, , can be set to zero to indicate there is no puncturing for that
pattern.
Sample content:
0 4 8 12
0
0123
01234567
0 1 2 3 4 5 6 7 8 9 10 11
In the sample content above, the first line contains the number of punctured symbols for each puncture pattern. 0
indicates that for the first puncture pattern there are 0 symbols punctured. 4 indicates that for the second puncture
pattern there are 4 symbols punctured. 8 indicates that for the third puncture pattern there are 8 symbols punctured. 12 indicates that for the fourth puncture pattern there are 12 symbols punctured. The first puncture pattern is
defined on line 2 and the second puncture pattern is defined on line 3, and so on. Each puncture pattern lists the
position of the punctured symbol starting from the end of the block. This means that the last symbol is numbered as
0 and the next to the last symbol is numbered as 1, and so on. Therefore, for the second puncture pattern defined
on line 3, number 0 indicates the last symbol in the block is punctured and number 1 indicates the second from the
last symbol is punctured. The values are entered in decimal format.
Default Field Polynomials
The default field polynomials used in the GUI for different symbol widths are given in Table 2-1. The user, however,
can enter any valid polynomial.
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Functional Description
Table 2-1. Default Field Polynomials
Symbol Width
Default Field Polynomial
3
Decimal Value
3
x +x+1
11
4
x4 + x + 1
19
5
2
5
x + x +1
37
6
x6 + x + 1
67
x7 + x3 + 1
137
x + x4 + x3 + x2 + 1
285
7
8
8
9
4
9
x +x +1
529
10
x10 + x3 + 1
1033
x11 + x2 + 1
2053
x + x6 + x4 + x + 1
4179
11
12
12
Signal Descriptions
Table 2-2 shows the definitions of the interface signals available with the RS Decoder IP Core.
Table 2-2. Interface Signal Descriptions
Port
Bits
I/O
Description
clk
1
I
System clock. This is the reference clock for input and output data.
rstn
1
I
System wide asynchronous active-low reset signal.
ibstart
1
I
Indicates that the data on din is the first information symbol of a new codeword.
din
3 - 12
I
Input data port. The wsymb parameter defines the port width of this signal.
dout
3 - 12
O
Output data port. The wsymb parameter defines the port width of this signal.
obstart
1
O
Output block start. Indicates the first output data of the codeword on the dout
port.
obend
1
O
Output block end. Indicates the last output data of the codeword on the dout
port.
outvalid
1
O
Output data valid. Indicates valid data is present on dout.
errfnd
1
O
Error found indicator. Asserted at the same time obend is asserted if the block
has at least one symbol in error.
O
Ready for input. Indicates the decoder is ready to receive input data. Typically,
this signal is high when the core is ready to read input symbols. This signal is
low when the decoder is busy processing a previous block of data and cannot
accept new block of data.
All Configurations
rfi
1
For Variable Check Symbols (When the Parameter Variable check symbols is Yes)
rfib
numchks
1
2-9
O
Ready for input block. Indicates that the decoder is ready to receive the first
information symbol in the block.
I
This port is used to provide the variable number of check symbols value. The
width of this port is defined as the number of bits required to represent the Max.
number of check symbols parameter value provided by the user. The width
of this port is defined as follows: ceil(log2(Max. number of check symbols)). The value at this port is read only when ibstart is high. The operator
ceil() stands for the next higher integer.
For Variable Block Size Type Only (When the Parameter Variable block size is “Yes”)
blocksize
3 - 12
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I
Variable block size value. The value at this port is read only when ibstart is
high. The wsymb parameter defines the port width of this signal.
15 Dynamic Block Reed-Solomon Decoder User’s Guide
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Functional Description
Table 2-2. Interface Signal Descriptions (Continued)
Port
Bits
I/O
Description
For Puncturing Mode (when Decoding mode is “Puncturing” and Number of puncture patterns is More than 1)
1-8
I
Puncture pattern select signal. The value on this port selects the puncturing pattern from the number of predefined patterns for the current block of data. The
width of this port is defined as ceil(log2(Number of puncture patterns)).
The value at this port is read only when ibstart is high.
1
I
Erasure. Asserted to indicate the input data symbol at the din port is erased.
ce
1
O
Clock enable. While this is de-asserted, the decoder will ignore all other synchronous inputs and maintain its current state.
sr
1
O
Synchronous reset. Asserted for at least one symbol duration in order to reinitialize the decoder state. Input data symbols sampled before sr is asserted are
not given at the output.
ddel
1
O
Original uncorrected data output. A delayed copy of the input data block. Data is
presented on ddel concurrently with the decoded block on dout. The wsymb
parameter defines the port width of this signal.
puncsel
For Erasure mode
ers
Optional I/Os
Error Counter. Provides the number of corrected errors in the most recent output block. The bus width errwidth is equal to the number of bits required to
represent the maximum possible number of correctable errors, as given in the
following equation:
When Block size type is Constant, errwidth is defined as errwidth =
ciel(log2((n-k+1)/2)) when Error Decoding mode is selected.
errwidth = ciel(log2(n-k-0.5)) when Erasure or Puncturing Decoding mode is
selected.
errcnt
1-8
O
When Block size type is Variable and Variable check symbols is No,
errwidth is defined as errwidth = ciel(log2((Number of check symbols+1)/2)) when Error Decoding mode is selected.
errwidth = ciel(log2(Number of check symbols-0.5)) when Erasure or Puncturing Decoding mode is selected.
When Variable check symbols is Yes, errwidth is defined as errwidth =
ciel(log2((Max. number of check symbols+1)/2)) The operator ciel() stands for
the next higher integer.
Erasure Counter. Provides a count of the number of erasures fed into the
decoder in the most recent input data block. The bus width erswidth is equal
to the number of bits required to represent the maximum possible number of
correctable erasures, as given in the following equation:
erscnt
1-8
O
When Block size type is Constant, erswidth is defined as erswidth =
ciel(log2(n-k-1.5)).
When Block size type is Variable, erswidth is defined as erswidth =
ciel(log2(Number of check symbols -1.5)) The operator ciel() stands for the next
higher integer.
fail
1
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O
Decoding failure indicator. Asserted at the same time obend is asserted to indicate that the block has more errors than the decoder can correct.
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Functional Description
Timing Specifications
The decoder receives the data in blocks. The assertion of signal ibstart indicates the first symbol of the new
block of data at the input of the decoder. The ibstart signal should be asserted only during the first clock cycle of
a data block. The ibstart signal should not be re-asserted until the decoder is ready to receive the next block of
data as indicated by rfib going high. The signal rfib can be used to generate the ibstart signal. If a new block
of input data has to be applied before the decoder is ready for a new block, the decoder operation should be reset
using the synchronous reset signal sr.
Figure 2-3 shows the I/O signals’ status after asynchronous reset rstn is asserted at the beginning of the block.
The output rfi goes high after reset to indicate the core is ready to receive input data. After ibstart signal is
asserted, the decoder reads in the data block sequentially and starts the decoding process. When the decoded
data is given at the output, obstart is asserted for one clock cycle during the first decoded output symbol. The
output obend is asserted for one clock cycle when the last decoded symbol is given at the dout port.
Figure 2-3. RS Decoder Normal Operation Timing Diagram
clk
rstn
ce
sr
rfi
rfib
ibstart
blocksize
n
o
p
numchks
c1
c2
c3
puncsel
p1
p2
p3
ers
din
CI0
CI1
CI2
CIp-3 CIp-2 CIp-1
dout
AO0
AO1
AO2
AOn-3 AOn-2 AOn-1
ddel
AI0
AI1
AI2
AIn-3 AIn-2 AIn-1
AI0
AI1
AI2
AIn-3 AIn-2 AIn-1 BI0
BI1
BI2
BIo-3 BIo-2 BIo-1
outvalid
obstart
obend
errfnd
errcnt
0
4
erscnt
0
2
fail
Figure 2-4 illustrates the output status when sr is asserted. When sr is asserted during the decoding process, it
reinitializes the decoder state similar to power on reset state. The output data stops appearing at the output. The
decoder operation can be started again by asserting the ibstart signal.
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Functional Description
Figure 2-4. Effect of Synchronous Reset on the Output Data from the Decoder
clk
rstn
ce
sr
rfi
rfib
ibstart
blocksize
n
numchks
c1
c2
c3
puncsel
p1
p2
p3
o
p
ers
din
AI0
AI1
AI2
AIn-3 AIn-2 AIn-1
BI0
BI1
BI2
BIo-3 BIo-2 BIo-1
CI0
CI1
CI2
CIp-3 CIp-2 CIp-1
dout
ddel
outvalid
obstart
obend
errfnd
errcnt
0
erscnt
0
fail
Figure 2-5 illustrates the effect of clock enable (ce) on the output data from RS Decoder. The decoder ignores all
other synchronous inputs and remains in its current state when ce is de-asserted. When ce is asserted, the
decoder goes back to the normal decoding process. In the figure, the data DX at din (that occurs during ce going
low) is not recognized by the decoder.
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Functional Description
Figure 2-5. Effect of Clock Enable on the Output Data from Decoder
clk
rstn
ce
sr
rfi
rfib
ibstart
blocksize
n
o
p
numchks
c1
c2
c3
puncsel
p1
p2
p3
ers
din
CI2
CIp-3 CIp-2 CIp-1
dout
AO0
AO1
AO2
AOn-3 AOn-2 AOn-1
ddel
AI0
AI1
AI2
AIn-3 AIn-2 AIn-1
AI0
AI1
AI2
AIn-3 AIn-2 AIn-1
BI0
BI1
BI2
BIo-3 BIo-2 BIo-1
CI0
DX
CI1
outvalid
obstart
obend
errfnd
errcnt
0
4
erscnt
0
2
fail
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19 Dynamic Block Reed-Solomon Decoder User’s Guide
Chapter 3:
Parameter Settings
The IPexpress™ tool is used to create IP and architectural modules in the Diamond and ispLEVER software. Refer
to “IP Core Generation” on page 24 for a description on how to generate the IP.
The RS Decoder IP core Configuration GUI allows the user to create a custom configuration or to select one of the
standard configurations: OC-192, CCSDS, DVB, ATSC, IEEE 802.16-2004 WirelessMAN-SCa/OFDM and IEEE
802.16-2004 WirelessMAN-SC. Table 3-1 provides the list of user configurable parameters for the RS Decoder IP
core.
Table 3-1. User Configurable Parameters
Parameter
Range/Options
Default
Custom, OC-192, CCSDS, DVB, ATSC, IEEE 802.16-2004
SCa, IEEE 802.16-2004 SC
OC-192
Yes/No
Yes
Core Configuration
Core configuration
Connect reset port to GSR
RS Parameters
wsymb
3 - 12 bits
8 bits
fpoly
5 - 8191
285
gstart
0 - 65535
0
rootspace
1 - 65535
1
Yes/No
No
Check Symbols
Variable check symbols
wsymb
Number of check symbols
4 - ((2
)-2). Maximum value is limited to 256.
16
Max. number of check symbols
4 - ((2wsymb)-2). Maximum value is limited to 128.
32
Variable} if Variable check symbols is checked. {Constant,
Variable} if Variable check symbols is not checked. {Constant}
if wsymb is 3 and Decoding mode is Erasure.
Constant
5 - ((2wsymb)-1) Default value is ((2wsymb)-1)
255
1 - (n-4)
239
Number of puncture patterns
1 - (n-k) when Block size is Constant. 1 - (Number of check
symbols) when Block size is Variable.
1
Puncture pattern file
Edit field to enter the file name directly or indirectly by using
the browse button.
Block Size Type
Block size type
Block size(n)
Information symbols(k)
Puncturing
Decoding Mode
Decoding mode
{Error, Erasure, Puncturing}
Error
{Automatic, Block, Distributed}
Automatic
Memory Type
Memory type
Optional Ports
ce
Yes/No
No
sr
Yes/No
No
errcnt
Yes/No
Yes
ddel
Yes/No
Yes
fail
Yes/No
No
erscnt
Yes/No
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Parameter Settings
RS Decoder Configuration GUI
Figure 3-1 shows the contents of the RS Decoder IP core Configuration GUI.
Figure 3-1. RS Decoder IP core Configuration GUI
Core Configuration
Selects between custom and pre-defined standard configurations. Table A-1 on page 33 defines the fixed parameter values for different standard configurations.
RS Parameters
Wsymb
This parameter sets symbol width.
Fpoly
This parameter sets the decimal value of the field polynomial. Table 2-1 on page 15 gives the default field polynomial values for different symbol widths.
Gstart
This parameter sets the offset value of the generator polynomial. The starting value for the first root of the generator polynomial is calculated as rootspace * gstart.
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Parameter Settings
Rootspace
This parameter sets the root spacing of the generator polynomial. The value of rootspace must satisfy the following
equation: GCD(rootspace, 2wsymb-1) = 1. GCD is Greatest Common Divisor.
Check Symbols
Variable Check Symbols
This option allows the number of check symbols to be varied through the port in addition to varying the block size
dynamically. In this case, the number of check symbols is defined through the input port numchks. This option is
available only when Block size type is Variable and Decoding mode is Error.
Number of Check Symbols
Constant value for the Number of check symbols in the codeword. This parameter is available when Block size type
is selected as Variable and Variable check symbols is not checked.
Max. Number of Check Symbols
Maximum value for number of check symbols provided through the input port numchks. This parameter selection is
available only when Variable check symbols is checked.
Block Size Type
This parameter specifies whether block size is provided as a constant value or varied through the input port. If
Block size type is selected as Variable, the block size is read from the input port blocksize. Options depend on Variable check symbols.
Block Size(n)
This parameter specifies the total number of symbols in the codeword. Defined only if Block size type is Constant.
Information Symbols(k)
This parameter specifies the number of information symbols in the codeword. Defined only if Block size type is
Constant. The value of k also depends on n as the maximum value of (n-k) is limited to 256
Puncturing
Number of Puncture Patterns
This is the number of pre-defined puncture patterns that can be dynamically selected using puncsel. This parameter is enabled when Decoding mode is selected as Puncturing.
Puncture Pattern File
This is the file containing the pre-defined puncture patterns. The format of the puncture pattern file is described in
the Puncture Pattern File Format section of this document. The browse button to load the puncture pattern file is
enabled when Decoding mode is selected as Puncturing. The file should have a .cfg extension.
Decoding Mode
Selects between different decoding modes. The selection of this parameter depends on the application requirements.
Memory Type
Specifies the type of memory used for storing input data. If Memory type is selected as Block, then EBR memory is
used. If Memory type is selected as Distributed then distributed memory is used. If Memory type is selected as
Automatic then memory will be selected in a most optimized way depending on the other parameters selected.
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Parameter Settings
Optional Ports
ce
Determines whether the input port ce (clock enable) is present.
sr
Determines whether the input port sr (synchronous reset) is present.
errcnt
Determines whether the output port errcnt (error count) is present.
ddel
Determines whether the output port ddel (delayed data) is present.
fail
Determines whether the output port fail (decoding failure) is present.
erscnt
Determines whether the output port erscnt (erasure count) is present.
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23 Dynamic Block Reed-Solomon Decoder User’s Guide
Chapter 4:
IP Core Generation
This chapter provides information on licensing the RS Decoder IP core, generating the core using the Diamond or
ispLEVER software IPexpress tool, running functional simulation, and including the core in a top-level design. The
Lattice RS Decoder IP core can be used in LatticeECP3, LatticeECP2/M, LatticeECP, LatticeSC/M, LatticeXP, and
LatticeXP2 device families.
Licensing the IP Core
An IP license is required to enable full, unrestricted use of the RS Decoder IP core in a complete, top-level design.
An IP license that specifies the IP core and device family is required to enable full use of the core in Lattice devices.
Instructions on how to obtain licenses for Lattice IP cores are given at:
http://www.latticesemi.com/products/intellectualproperty/aboutip/isplevercoreonlinepurchas.cfm
Users may download and generate the IP core and fully evaluate the core through functional simulation and implementation (synthesis, map, place and route) without an IP license. The RS Decoder IP core core also supports Lattice’s IP hardware evaluation capability, which makes it possible to create versions of the IP core that operate in
hardware for a limited time (approximately four hours) without requiring an IP license (see “Instantiating the Core”
on page 28 for further details). However, a license is required to enable timing simulation, to open the design in the
Diamond or ispLEVER EPIC tool, and to generate bitstreams that do not include the hardware evaluation timeout
limitation.
Getting Started
The RS Decoder IP core is available for download from the Lattice IP Server using the IPexpress tool. The IP files
are automatically installed using ispUPDATE technology in any customer-specified directory. After the IP core has
been installed, the IP core will be available in the IPexpress GUI dialog box shown in Figure 4-1.
The IPexpress tool GUI dialog box for the RS Decoder IP core is shown in Figure 4-1. To generate a specific IP
core configuration the user specifies:
• Project Path – Path to the directory where the generated IP files will be located.
• File Name – “username” designation given to the generated IP core and corresponding folders and files.
• (Diamond) Module Output – Verilog or VHDL.
• (ispLEVER) Design Entry Type – Verilog HDL or VHDL.
• Device Family – Device family to which IP is to be targeted (e.g. LatticeSCM, Lattice ECP2M, LatticeECP3,
etc.). Only families that support the particular IP core are listed.
• Part Name – Specific targeted part within the selected device family.
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IP Core Generation
Figure 4-1. IPexpress Tool Dialog Box (Diamond Version)
Note that if the IPexpress tool is called from within an existing project, Project Path, Module Output (Design Entry in
ispLEVER), Device Family and Part Name default to the specified project parameters. Refer to the IPexpress tool
online help for further information.
To create a custom configuration, the user clicks the Customize button in the IPexpress tool dialog box to display
the RS Decoder IP core Configuration GUI, as shown in Figure 4-2. From this dialog box, the user can select the IP
parameter options specific to their application. Refer to “Parameter Settings” on page 16for more information on the
parameter settings.
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IP Core Generation
Figure 4-2. Configuration GUI (Diamond Version)
IPexpress-Created Files and Top Level Directory Structure
When the user clicks the Generate button in the IP Configuration dialog box, the IP core and supporting files are
generated in the specified “Project Path” directory. The directory structure of the generated files is shown in
Figure 4-3.
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IP Core Generation
Figure 4-3. Lattice RS Decoder IP core Directory Structure
Table 4-1 provides a list of key files and directories created by the IPexpress tool and how they are used. The IPexpress tool creates several files that are used throughout the design cycle. The names of most of the created files
are customized to the user’s module name specified in the IPexpress tool.
Table 4-1. File List
File
Description
_inst.v
This file provides an instance template for the IP.
.v
This file provides the RS Decoder core for simulation.
_beh.v
This file provides a behavioral simulation model for the RS Decoder core.
_bb.v
This file provides the synthesis black box for the user’s synthesis.
.ngo
The ngo files provide the synthesized IP core.
.lpc
This file contains the IPexpress tool options used to recreate or modify the core in the
IPexpress tool.
.ipx
The IPX file holds references to all of the elements of an IP or Module after it is generated
from the IPexpress tool (Diamond version only). The file is used to bring in the appropriate
files during the design implementation and analysis. It is also used to re-load parameter
settings into the IP/Module generation GUI when an IP/Module is being re-generated.
_top.[v,vhd]
This file provides a module which instantiates the RS Decoder core. This file can be easily
modified for the user's instance of the RS Decoder core. This file is located in the
rsdec_eval/_/src/rtl/top/ directory.
_generate.tcl
Created when GUI “Generate” button is pushed, invokes generation, may be run from
command line.
_generate.log
IPexpress scripts log file.
_gen.log
IPexpress IP generation log file
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IP Core Generation
Instantiating the Core
The generated RS Decoder IP core package includes black-box (_bb.v) and instance (_inst.v) templates that can be used to instantiate the core in a top-level design. An example RTL top-level
reference source file that can be used as an instantiation template for the IP core is provided in
\\rsdec_eval\\src\rtl\top. Users may also use this top-level reference as
the starting template for the top-level for their complete design.
Running Functional Simulation
Simulation support for the RS Decoder IP core is provided for Aldec Active-HDL (Verilog and VHDL) simulator,
Mentor Graphics ModelSim simulator. The functional simulation includes a configuration-specific behavioral model
of the RS Decoder IP core. The test bench sources stimulus to the core, and monitors output from the core. The
generated IP core package includes the configuration-specific behavior model (_beh.v) for functional
simulation in the “Project Path” root directory. The simulation scripts supporting ModelSim evaluation simulation is
provided in \\rsdec_eval\\sim\modelsim\scripts. The simulation script
supporting Aldec evaluation simulation is provided in
\\rsdec_eval\\sim\aldec\scripts. Both Modelsim and Aldec simulation is
supported via test bench files provided in \\rsdec_eval\testbench. Models required for simulation are provided in the corresponding \models folder. Users may run the Aldec evaluation simulation by doing
the following:
1. Open Active-HDL.
2. Under the Tools tab, select Execute Macro.
3. 3. Browse to folder \\rsdec_eval\\sim\aldec\scripts and execute one
of the "do" scripts shown.
Users may run the ModelSim evaluation simulation by doing the following:
1. Open ModelSim.
2. Under the File tab, select Change Directory and choose the folder
\rsdec_eval\\sim\modelsim\scripts.
3. Under the Tools tab, select Execute Macro and execute the ModelSim “do” script shown.
Note: When the simulation completes, a pop-up window will appear asking “Are you sure you want to finish?”
Answer No to analyze the results (answering Yes closes ModelSim).
Synthesizing and Implementing the Core in a Top-Level Design
Synthesis support for the RS Decoder IP core is provided for Mentor Graphics Precision or Synopsys Synplify. The
RS Decoder IP core itself is synthesized and is provided in NGO format when the core is generated in IPexpress.
Users may synthesize the core in their own top-level design by instantiating the core in their top-level as described
previously and then synthesizing the entire design with either Synplify or Precision RTL Synthesis. The following
text describes the evaluation implementation flow for Windows platforms. The flow for Linux and UNIX platforms is
described in the Readme file included with the IP core. The top-level files _top.v are provided in
\\rsdec_eval\\src\rtl\top. Push-button implementation of the reference
design is supported via Diamond or ispLEVER project files, .syn, located in the following directory:
\\rsdec_eval\\impl\(synplify or precision). To use these project files
using Synplify:
To use this project file in Diamond:
1. Choose File > Open > Project.
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IP Core Generation
2. Browse to
\\rsdec_eval\\impl\synplify (or precision) in the Open Project
dialog box.
3. Select and open .ldf. At this point, all of the files needed to support top-level synthesis and implementation will be imported to the project.
4. Select the Process tab in the left-hand GUI window.
5. Implement the complete design via the standard Diamond GUI flow.
To use this project file in ispLEVER:
1. Choose File > Open Project.
2. Browse to
\\rsdec_eval\\impl\synplify (or precision) in the Open Project
dialog box.
3. Select and open .syn. At this point, all of the files needed to support top-level synthesis and implementation will be imported to the project.
4. Select the device top-level entry in the left-hand GUI window.
5. Implement the complete design via the standard ispLEVER GUI flow.
Hardware Evaluation
The RS Decoder IP core supports Lattice’s IP hardware evaluation capability, which makes it possible to create versions of the IP core that operate in hardware for a limited period of time (approximately four hours) without requiring
the purchase of an IP license. It may also be used to evaluate the core in hardware in user-defined designs.
Enabling Hardware Evaluation in Diamond
Choose Project > Active Strategy > Translate Design Settings. The hardware evaluation capability may be
enabled/disabled in the Strategy dialog box. It is enabled by default.
Enabling Hardware Evaluation in ispLEVER
In the Processes for Current Source pane, right-click the Build Database process and choose Properties from the
dropdown menu. The hardware evaluation capability may be enabled/disabled in the Properties dialog box. It is
enabled by default.
Updating/Regenerating the IP Core
By regenerating an IP core with the IPexpress tool, you can modify any of its settings including device type, design
entry method, and any of the options specific to the IP core. Regenerating can be done to modify an existing IP
core or to create a new but similar one.
Regenerating an IP Core in Diamond
To regenerate an IP core in Diamond:
1. In IPexpress, click the Regenerate button.
2. In the Regenerate view of IPexpress, choose the IPX source file of the module or IP you wish to regenerate.
3. IPexpress shows the current settings for the module or IP in the Source box. Make your new settings in the Target box.
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IP Core Generation
4. If you want to generate a new set of files in a new location, set the new location in the IPX Target File box. The
base of the file name will be the base of all the new file names. The IPX Target File must end with an .ipx extension.
5. Click Regenerate. The module’s dialog box opens showing the current option settings.
6. In the dialog box, choose the desired options. To get information about the options, click Help. Also, check the
About tab in IPexpress for links to technical notes and user guides. IP may come with additional information. As
the options change, the schematic diagram of the module changes to show the I/O and the device resources
the module will need.
7. To import the module into your project, if it’s not already there, select Import IPX to Diamond Project (not
available in stand-alone mode).
8. Click Generate.
9. Check the Generate Log tab to check for warnings and error messages.
10.Click Close.
The IPexpress package file (.ipx) supported by Diamond holds references to all of the elements of the generated IP
core required to support simulation, synthesis and implementation. The IP core may be included in a user's design
by importing the .ipx file to the associated Diamond project. To change the option settings of a module or IP that is
already in a design project, double-click the module’s .ipx file in the File List view. This opens IPexpress and the
module’s dialog box showing the current option settings. Then go to step 6 above.
Regenerating an IP Core in ispLEVER
To regenerate an IP core in ispLEVER:
1. In the IPexpress tool, choose Tools > Regenerate IP/Module.
2. In the Select a Parameter File dialog box, choose the Lattice Parameter Configuration (.lpc) file of the IP core
you wish to regenerate, and click Open.
3. The Select Target Core Version, Design Entry, and Device dialog box shows the current settings for the IP core
in the Source Value box. Make your new settings in the Target Value box.
4. If you want to generate a new set of files in a new location, set the location in the LPC Target File box. The base
of the .lpc file name will be the base of all the new file names. The LPC Target File must end with an .lpc extension.
5. Click Next. The IP core’s dialog box opens showing the current option settings.
6. In the dialog box, choose desired options. To get information about the options, click Help. Also, check the
About tab in the IPexpress tool for links to technical notes and user guides. The IP core might come with additional information. As the options change, the schematic diagram of the IP core changes to show the I/O and
the device resources the IP core will need.
7. Click Generate.
8. Click the Generate Log tab to check for warnings and error messages.
IPUG52_01.6, December 2010
30 Dynamic Block Reed-Solomon Decoder User’s Guide
Chapter 5:
Support Resources
This chapter contains information about Lattice Technical Support, additional references, and document revision
history.
Lattice Technical Support
There are a number of ways to receive technical support.
Online Forums
The first place to look is Lattice Forums (http://www.latticesemi.com/support/forums.cfm). Lattice Forums contain a
wealth of knowledge and are actively monitored by Lattice Applications Engineers.
Telephone Support Hotline
Receive direct technical support for all Lattice products by calling Lattice Applications from 5:30 a.m. to 6 p.m.
Pacific Time.
• For USA & Canada: 1-800-LATTICE (528-8423)
• For other locations: +1 503 268 8001
In Asia, call Lattice Applications from 8:30 a.m. to 5:30 p.m. Beijing Time (CST), +0800 UTC. Chinese and English
language only.
• For Asia: +86 21 52989090
E-mail Support
• techsupport@latticesemi.com
• techsupport-asia@latticesemi.com
Local Support
Contact your nearest Lattice Sales Office.
Internet
www.latticesemi.com
References
• I. S. Reed, M. T. Shih, and T. K. Truong, “VLSI design of inverse-free Berlekamp-Massey algorithm,” Proc. IEEE,
Part E, vol. 138, pp. 295-298, September 1991.
• S. Kwon and H. Shin, “An area-efficient VLSI architecture of a Reed-Solomon decoder/encoder for digital VCRs,”
IEEE Trans. Consumer Electronics, pp. 1019-1027, Nov. 1997.
LatticeEC/ECP
• HB1000, LatticeECP/EC Family Handbook
LatticeECP2M
• HB1003, LatticeECP2M Family Handbook
LatticeECP3
• HB1009, LatticeECP3 Family Handbook
IPUG52_01.6, December 2010
31 Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Support Resources
LatticeSC/M
• DS1004, LatticeSC/M Family Data Sheet
LatticeXP
• HB1001, LatticeXP Family Handbook
LatticeXP2
• DS1009, Lattice XP2 Datasheet
Related Information
For more information regarding core usage and design verification, refer to the Reed-Solomon Decoder IP Core
User’s Guide.
Revision History
Date
Document
Version
IP
Version
Change Summary
March 2006
01.0
2.0
Initial release.
August 2006
01.1
3.0
Core version 3.0: Full support of IPexpress flow, including
LatticeECP/EC, LatticeECP2, LatticeSC, and LatticeXP.
January 2007
01.2
3.1
Updated LatticeECP/EC, LatticeECP2, LatticeXP and LatticeSC appendices. Added support for the LatticeECP2M FPGA family.
May 2007
01.3
3.2
Added support for LatticeXP2 FPGA family.
May 2009
01.4
3.3
Added support for LatticeECP3 FPGA family.
Added VHDL flow.
Added Aldec Active-HDL simulation and Linux/Solaris platform support.
July 2010
01.5
3.3
Divided document into chapters. Added table of contents.
Added Quick Facts tables in Chapter 1, “Introduction.”
Added new content in Chapter 4, “IP Core Generation.”
December 2010
01.6
IPUG52_01.6, December 2010
3.4
Added support for Diamond software throughout.
32 Dynamic Block Reed-Solomon Decoder User’s Guide
Appendix A:
Resource Utilization
This appendix gives resource utilization information for Lattice FPGAs using the RS Decoder IP core.
IPexpress is the Lattice IP configuration utility, and is included as a standard feature of the Diamond and ispLEVER
design tools. Details regarding the usage of IPexpress can be found in the IPexpress and Diamond or ispLEVER
help system. For more information on the Diamond or ispLEVER design tools, visit the Lattice web site at:
www.latticesemi.com/software.
Table A-1 gives the parameter settings for the standard configurations shown in Table A-2 through Table A-8.
Table A-1. Parameter Settings for Standard Configurations
Core Configuration
OC-192
(config1)
Parameter Name
CCSDS
(config2)
DVB
(config3)
ATSC
(config4)
IEEE 802.16-2004
WirelessMA-SCa or IEEE 802.16-2004
WirelessMA-OFDM WirelessMAN-SC
(config5)
(config6)
RS Parameters
wsymb
8
8
8
8
8
8
285
391
285
285
285
285
gstart
0
112
0
0
0
0
rootspace
1
11
1
1
1
1
Variable check symbols
No
No
No
No
No
Yes
Number of check symbols
NA
NA
NA
NA
16
NA
Max. number of check symbols
NA
NA
NA
NA
NA
32
Constant
Constant
Constant
Constant
Variable
Variable
fpoly
Check Symbols
Block Size Type
Block size type
Block size(n)
255
255
204
207
NA
NA
InfoSymbols(k)
239
223
188
187
NA
NA
NA
NA
NA
NA
4
NA
Error
Error
Error
Error
Puncturing
Error
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
No
No
No
No
No
No
Puncturing
Number of puncture patterns
Decoding Mode
Decoding mode
Memory Type
Memory type
Optional Input/Output Ports
ce
sr
No
No
No
No
No
No
errcnt
Yes
Yes
Yes
Yes
Yes
Yes
ddel
Yes
Yes
Yes
Yes
Yes
Yes
fail
No
No
No
No
No
No
erscnt
NA
NA
NA
NA
Yes
NA
IPUG52_01.6, December 2010
33 Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Resource Utilization
LatticeECP and LatticeEC FPGAs
Table A-2. Performance and Resource Utilization1
Slices
LUTs
Registers
sysMEM™
EBRs
I/Os
fMAX (MHz)
OC-192
588
1171
795
2
37
123
CCSDS
980
1947
1349
2
38
114
DVB
604
1196
802
2
37
124
IPexpress User-Configurable Mode
ATSC
766
1520
969
2
37
113
IEEE 802.16-2004 WirelessMAN SCa
927
1835
1279
2
51
116
IEEE 802.16-2004 WirelessMAN SC
1044
2066
1486
2
52
104
1. Performance and utilization data are generated using an LFEC/P20E-5F672C device with Lattice Diamond 1.0 and Synplify Pro for Lattice
D-2009.12L-1 software. Performance may vary when using a different software version or targeting a different device density or speed
grade within the LatticeECP/EC family.
Ordering Part Number
The Ordering Part Number (OPN) for the RS Decoder core targeting LatticeECP/EC devices is RSDEC-DBLK-E2U3.
LatticeECP2 and LatticeECP2S FPGAs
Table A-3. Performance and Resource Utilization1
IPexpress User-Configurable Mode
Registers
sysMEM
EBRs
I/Os
fMAX (MHz)
1117
791
2
37
175
1917
1322
2
38
157
Slices
LUTs
OC-192
562
CCSDS
963
DVB
591
1173
792
2
37
150
ATSC
756
1500
960
2
37
166
IEEE 802.16-2004 WirelessMAN SCa
917
1818
1252
2
51
152
IEEE 802.16-2004 WirelessMAN SC
1037
2056
1493
2
52
137
1. Performance and utilization data are generated using an LFE2-50E/S-7F672C device with with Lattice Diamond 1.0 and Synplify Pro for
Lattice D-2009.12L-1 software. Performance may vary when using a different software version or targeting a different device density or
speed grade within the LatticeECP2/S family.
Ordering Part Number
The Ordering Part Number (OPN) for the RS Decoder core targeting LatticeECP2/S devices is
RSDEC-DBLK-P2-U3.
IPUG52_01.6, December 2010
34 Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Resource Utilization
LatticeECP2M and LatticeECP2MS FPGAs
Table A-4. Performance and Resource Utilization1
Slices
LUTs
Registers
sysMEM
EBRs
I/Os
fMAX (MHz)
OC-192
562
1117
791
2
37
169
CCSDS
963
1917
1322
2
38
163
DVB
591
1173
792
2
37
178
ATSC
756
1500
960
2
37
160
IEEE 802.16-2004 WirelessMAN SCa
917
1818
1252
3
51
151
IEEE 802.16-2004 WirelessMAN SC
1037
2056
1493
3
52
145
IPexpress User-Configurable Mode
1. Performance and utilization data are generated using an LFE2M35E/SE-7F484C device with with Lattice Diamond 1.0 and Synplify Pro for
Lattice D-2009.12L-1 software. Performance may vary when using a different software version or targeting a different device density or
speed grade within the LatticeECP2M/S family.
Ordering Part Number
The Ordering Part Number (OPN) for the RS Decoder core targeting LatticeECP2M/S devices is
RSDEC-DBLK-PM-U3.
LatticeECP3 FPGAs
Table A-5. Performance and Resource Utilization1
Slices
LUTs
Registers
sysMEM
EBRs
I/Os
fMAX (MHz)
OC-192
564
1062
791
2
37
148
CCSDS
990
1884
1322
2
38
149
DVB
591
1123
792
2
37
156
IPexpress User-Configurable Mode
ATSC
776
1476
960
2
37
144
IEEE 802.16-2004 WirelessMAN SCa
912
1746
1252
2
51
145
IEEE 802.16-2004 WirelessMAN SC
1067
2031
1493
2
52
142
1. Performance and utilization data are generated using an LFE3-95E-8FN672CES device with with Lattice Diamond 1.0 and Synplify Pro for
Lattice D-2009.12L-1 software. Performance may vary when using a different software version or targeting a different device density or
speed grade within the LatticeECP3 family.
Ordering Part Number
The Ordering Part Number (OPN) for the RS Decoder core targeting LatticeECP3 devices is RSDEC-DBLK-P3-U3.
IPUG52_01.6, December 2010
35 Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Resource Utilization
LatticeXP FPGAs
Table A-6. Performance and Resource Utilization1
Slices
LUTs
Registers
sysMEM
EBRs
I/Os
fMAX (MHz)
OC-192
588
1171
795
2
37
110
CCSDS
980
1947
1349
2
38
108
DVB
604
1196
802
2
37
111
ATSC
766
1520
969
2
37
103
IEEE 802.16-2004 WirelessMAN SCa
928
1837
1279
2
51
109
IEEE 802.16-2004 WirelessMAN SC
1044
2066
1486
2
52
85
IPexpress User-Configurable Mode
1. Performance and utilization data are generated using an LFXP20E-5F484C device with with Lattice Diamond 1.0 and Synplify Pro for Lattice D-2009.12L-1 software. Performance may vary when using a different software version or targeting a different device density or speed
grade within the LatticeXP family.
Ordering Part Number
The Ordering Part Number (OPN) for the RS Decoder core targeting LatticeXP devices is RSDEC-DBLK-XP-U3.
LatticeXP2 FPGAs
Table A-7. Performance and Resource Utilization1
Slices
LUTs
Registers
sysMEM
EBRs
I/Os
fMAX (MHz)
OC-192
562
1117
791
2
37
140
CCSDS
963
1917
1322
2
38
128
DVB
591
1173
792
2
37
157
IPexpress User-Configurable Mode
ATSC
756
1500
960
2
37
128
IEEE 802.16-2004 WirelessMAN SCa
917
1818
1252
2
51
126
IEEE 802.16-2004 WirelessMAN SC
1037
2056
1493
2
52
127
1. Performance and utilization data are generated using an LFXP2-30E-7F484C device with with Lattice Diamond 1.0 and Synplify Pro for Lattice D-2009.12L-1 software. Performance may vary when using a different software version or targeting a different device density or speed
grade within the LatticeXP2 family.
Ordering Part Number
The Ordering Part Number (OPN) for the RS Decoder core targeting LatticeXP2 devices is RSDEC-DBLK-X2-U3.
IPUG52_01.6, December 2010
36 Dynamic Block Reed-Solomon Decoder User’s Guide
Lattice Semiconductor
Resource Utilization
LatticeSC and LatticeSCM FPGAs
Table A-8. Performance and Resource Utilization1
Slices
LUTs
Registers
sysMEM
EBRs
I/Os
fMAX (MHz)
OC-192
591
1113
803
2
37
267
CCSDS
1033
1958
1348
2
38
245
DVB
642
1219
804
2
37
287
ATSC
804
1537
970
2
37
253
IEEE 802.16-2004 WirelessMAN SCa
965
1833
1276
2
51
240
IEEE 802.16-2004 WirelessMAN SC
1107
2101
1501
2
52
238
IPexpress User-Configurable Mode
1. Performance and utilization data are generated using an LFSC/M3GA25E-7F900C device with with Lattice Diamond 1.0 and Synplify Pro
for Lattice D-2009.12L-1 software. Performance may vary when using a different software version or targeting a different device density or
speed grade within the LatticeSC/M family.
Ordering Part Number
The Ordering Part Number (OPN) for the RS Decoder core targeting LatticeSC/M devices is
RSDEC-DBLK-SC-U3.
IPUG52_01.6, December 2010
37 Dynamic Block Reed-Solomon Decoder User’s Guide