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mkoko
Visitor
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3,663 Views
Registered: ‎11-04-2013

WARNING:Xst:2254 - Area constraint could not be met for block <LDPC_decoder>, final ratio is 1686.

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when i made syn for my code the following warning appear 

 

Started : "Launching ISE Text Editor to edit LDPC_decoder.v".
WARNING:Xst:2254 - Area constraint could not be met for block <LDPC_decoder>, final ratio is 1686.

 

after it syn doesnot  change till 24 hour i donot know what is the problem 

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gszakacs
Professor
Professor
4,498 Views
Registered: ‎08-14-2007

It looks like you're trying to pack ten pounds of logic into a one pound sack...

 

Your synthesis usage report shows many thousands of multiplexers among other things.  The "final ratio" of 1686 says you have 16.86 times as much logic as would fit into the device.  This means it's time to re-visit your code and try to see where all the resources are getting used.  It might come from large loops (generate or procedural).  It might come from memory being synthesized from fip-flops instead of block RAMs.

 

In any case you need to address this problem at the source rather than expecting Map to somehow pack all that stuff into your part.

 

If you're not sure where the usage is in your design, you can try removing individual modules to see how much that reduces the design size.

=========================================================================
Advanced HDL Synthesis Report

Macro Statistics
# RAMs                                                 : 364
 136x16-bit dual-port block RAM                        : 103
 136x16-bit single-port distributed RAM                : 17
 78x3-bit single-port distributed Read Only RAM        : 1
 78x37-bit dual-port distributed RAM                   : 120
 78x49-bit single-port distributed Read Only RAM       : 2
 78x56-bit single-port distributed Read Only RAM       : 1
 78x8-bit dual-port distributed RAM                    : 120
# Multipliers                                          : 5
 32x3-bit multiplier                                   : 4
 7x6-bit multiplier                                    : 1
# Adders/Subtractors                                   : 5071
 11-bit subtractor                                     : 1
 16-bit adder                                          : 1200
 16-bit subtractor                                     : 1440
 2-bit adder                                           : 2
 3-bit adder                                           : 1084
 3-bit subtractor                                      : 843
 4-bit adder                                           : 120
 4-bit subtractor                                      : 124
 5-bit adder                                           : 120
 6-bit adder                                           : 120
 7-bit adder                                           : 7
 7-bit addsub                                          : 2
 8-bit adder                                           : 5
 8-bit subtractor                                      : 3
# Counters                                             : 1091
 13-bit down counter                                   : 1
 13-bit up counter                                     : 1
 2-bit up counter                                      : 120
 3-bit up counter                                      : 601
 6-bit up counter                                      : 1
 7-bit up counter                                      : 125
 8-bit up counter                                      : 2
 9-bit up counter                                      : 240
# Registers                                            : 116999
 Flip-Flops                                            : 116999
# Comparators                                          : 3979
 13-bit comparator equal                               : 1
 16-bit comparator greater                             : 480
 16-bit comparator lessequal                           : 120
 3-bit comparator equal                                : 2522
 3-bit comparator greater                              : 240
 3-bit comparator lessequal                            : 240
 3-bit comparator not equal                            : 120
 32-bit comparator greater                             : 122
 6-bit comparator equal                                : 120
 6-bit comparator greater                              : 1
 7-bit comparator greater                              : 5
 7-bit comparator lessequal                            : 1
 8-bit comparator equal                                : 1
 8-bit comparator greater                              : 4
 8-bit comparator lessequal                            : 2
# Multiplexers                                         : 74590
 1-bit 1920-to-1 multiplexer                           : 1
 1-bit 2-to-1 multiplexer                              : 40743
 1-bit 4-to-1 multiplexer                              : 720
 10-bit 2-to-1 multiplexer                             : 8
 11-bit 2-to-1 multiplexer                             : 9
 12-bit 2-to-1 multiplexer                             : 8
 13-bit 2-to-1 multiplexer                             : 8
 14-bit 2-to-1 multiplexer                             : 8
 15-bit 2-to-1 multiplexer                             : 8
 16-bit 2-to-1 multiplexer                             : 29040
 16-bit 4-to-1 multiplexer                             : 120
 16-bit 8-to-1 multiplexer                             : 120
 2-bit 2-to-1 multiplexer                              : 254
 2-bit 3-to-1 multiplexer                              : 2
 2-bit 4-to-1 multiplexer                              : 1
 3-bit 2-to-1 multiplexer                              : 1940
 32-bit 2-to-1 multiplexer                             : 120
 4-bit 2-to-1 multiplexer                              : 488
 49-bit 2-to-1 multiplexer                             : 2
 5-bit 2-to-1 multiplexer                              : 128
 56-bit 2-to-1 multiplexer                             : 1
 6-bit 2-to-1 multiplexer                              : 368
 64-bit 2-to-1 multiplexer                             : 360
 7-bit 2-to-1 multiplexer                              : 22
 8-bit 2-to-1 multiplexer                              : 103
 9-bit 2-to-1 multiplexer                              : 8
# Logic shifters                                       : 493
 104-bit shifter logical right                         : 3
 112-bit shifter logical right                         : 480
 3824-bit shifter logical right                        : 6
 91-bit shifter logical right                          : 4
# Xors                                                 : 3000
 1-bit xor2                                            : 2520
 32-bit xor2                                           : 480

=========================================================================
-- Gabor

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1 Reply
gszakacs
Professor
Professor
4,499 Views
Registered: ‎08-14-2007

It looks like you're trying to pack ten pounds of logic into a one pound sack...

 

Your synthesis usage report shows many thousands of multiplexers among other things.  The "final ratio" of 1686 says you have 16.86 times as much logic as would fit into the device.  This means it's time to re-visit your code and try to see where all the resources are getting used.  It might come from large loops (generate or procedural).  It might come from memory being synthesized from fip-flops instead of block RAMs.

 

In any case you need to address this problem at the source rather than expecting Map to somehow pack all that stuff into your part.

 

If you're not sure where the usage is in your design, you can try removing individual modules to see how much that reduces the design size.

=========================================================================
Advanced HDL Synthesis Report

Macro Statistics
# RAMs                                                 : 364
 136x16-bit dual-port block RAM                        : 103
 136x16-bit single-port distributed RAM                : 17
 78x3-bit single-port distributed Read Only RAM        : 1
 78x37-bit dual-port distributed RAM                   : 120
 78x49-bit single-port distributed Read Only RAM       : 2
 78x56-bit single-port distributed Read Only RAM       : 1
 78x8-bit dual-port distributed RAM                    : 120
# Multipliers                                          : 5
 32x3-bit multiplier                                   : 4
 7x6-bit multiplier                                    : 1
# Adders/Subtractors                                   : 5071
 11-bit subtractor                                     : 1
 16-bit adder                                          : 1200
 16-bit subtractor                                     : 1440
 2-bit adder                                           : 2
 3-bit adder                                           : 1084
 3-bit subtractor                                      : 843
 4-bit adder                                           : 120
 4-bit subtractor                                      : 124
 5-bit adder                                           : 120
 6-bit adder                                           : 120
 7-bit adder                                           : 7
 7-bit addsub                                          : 2
 8-bit adder                                           : 5
 8-bit subtractor                                      : 3
# Counters                                             : 1091
 13-bit down counter                                   : 1
 13-bit up counter                                     : 1
 2-bit up counter                                      : 120
 3-bit up counter                                      : 601
 6-bit up counter                                      : 1
 7-bit up counter                                      : 125
 8-bit up counter                                      : 2
 9-bit up counter                                      : 240
# Registers                                            : 116999
 Flip-Flops                                            : 116999
# Comparators                                          : 3979
 13-bit comparator equal                               : 1
 16-bit comparator greater                             : 480
 16-bit comparator lessequal                           : 120
 3-bit comparator equal                                : 2522
 3-bit comparator greater                              : 240
 3-bit comparator lessequal                            : 240
 3-bit comparator not equal                            : 120
 32-bit comparator greater                             : 122
 6-bit comparator equal                                : 120
 6-bit comparator greater                              : 1
 7-bit comparator greater                              : 5
 7-bit comparator lessequal                            : 1
 8-bit comparator equal                                : 1
 8-bit comparator greater                              : 4
 8-bit comparator lessequal                            : 2
# Multiplexers                                         : 74590
 1-bit 1920-to-1 multiplexer                           : 1
 1-bit 2-to-1 multiplexer                              : 40743
 1-bit 4-to-1 multiplexer                              : 720
 10-bit 2-to-1 multiplexer                             : 8
 11-bit 2-to-1 multiplexer                             : 9
 12-bit 2-to-1 multiplexer                             : 8
 13-bit 2-to-1 multiplexer                             : 8
 14-bit 2-to-1 multiplexer                             : 8
 15-bit 2-to-1 multiplexer                             : 8
 16-bit 2-to-1 multiplexer                             : 29040
 16-bit 4-to-1 multiplexer                             : 120
 16-bit 8-to-1 multiplexer                             : 120
 2-bit 2-to-1 multiplexer                              : 254
 2-bit 3-to-1 multiplexer                              : 2
 2-bit 4-to-1 multiplexer                              : 1
 3-bit 2-to-1 multiplexer                              : 1940
 32-bit 2-to-1 multiplexer                             : 120
 4-bit 2-to-1 multiplexer                              : 488
 49-bit 2-to-1 multiplexer                             : 2
 5-bit 2-to-1 multiplexer                              : 128
 56-bit 2-to-1 multiplexer                             : 1
 6-bit 2-to-1 multiplexer                              : 368
 64-bit 2-to-1 multiplexer                             : 360
 7-bit 2-to-1 multiplexer                              : 22
 8-bit 2-to-1 multiplexer                              : 103
 9-bit 2-to-1 multiplexer                              : 8
# Logic shifters                                       : 493
 104-bit shifter logical right                         : 3
 112-bit shifter logical right                         : 480
 3824-bit shifter logical right                        : 6
 91-bit shifter logical right                          : 4
# Xors                                                 : 3000
 1-bit xor2                                            : 2520
 32-bit xor2                                           : 480

=========================================================================
-- Gabor

View solution in original post