Subversion Repositories ht_tunnel

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        HyperTransport Tunnel

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This project describes a HyperTransport tunnel for hardware synthesis using

the SystemC C++ API.  It was developped to be integrated as a core into a

larger hardware project.  You can either synthesize the core using a SystemC

synthesis tool or simulate it using any C++ compiler.  The design was

developped using SystemC 2.0.1

The tunnel is technology independent, so it can be used with any technology

(Xilinx FPGAs,  Altera FPGAs, standard cell proces, etc.)  The design uses

synchronous dual-port (one read and one write port) memories by having input

and outputs ports to those memories.  So when instanciating the design, you

must connect those ports either to memories in a real circuit or to a memory

model in simulation.

The design has many options and to change them, you need to modify the file

rtl/systemc/core_synth/constants.h.  It contains all the options and

configuration option available.  This includes various modes : if the retry

mode is enabled, if DirectRoute is enabled, etc.  It is also used to setup

the Configuration Space Registers : the address space used by the application,

the ID number of the application, etc.

For code documentation, you can run doxygen (a documenation tool) with the

doxygen.config.  It will generate HTML documentation in doc/doxygen/html

For higher level documentation, look in the doc folder.  At the moment of

writing this readme, the doc folder is empty but hopefully by the time you

read this there will be some proper documentation.  But at least remember

that the source code is fairly well documented (in .h files) so don't be

afraid to go read at least the module descriptions in the .h files.

For synthesis

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The design was originally designed for the Synopsys SystemC Compiler tool,

but it is now discontinued.  Alternatives are Celoxica Agility Compiler and

Forte Cynthesizer.  Agility 1.0 is not compatible with the core but version

2.0 might be when it is released.  I have not had the chance to try

Cynthesizer so I do not know if it works.  If you have the chance of trying

it, let me know!  I have synthesized multiple configurations of the design

and tested them in post-synthesis simulation, but those versions are useless

in a real application since the tunnel needs to be re-synthesized when the

CSR configuration changes, and every project usually has a different CSR

configuration.

For simulation in a larger project

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To simulate it within a larger SystemC project, just include all the source

files in rtl/systemc in your project and instanciate the top level

vc_ht_tunnel_l1 module to use just like any SystemC module.  But bear in mind

that this is an RTL description, so simulation is pretty slow.

For simulation in ModelSim

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The .do file contains most of the commands necessary to compile the design

in ModelSim and run the main testbench, but to simulate it in your project

you will need a top level that instanciates the design and links it with

other designs.  In other words, the .do file is only a set of commands to

get you started and run a testbench.  ModelSim allows to run SystemC alongside

netlists, VHDL, Verilog or anything supported my ModelSim.

For simulation alone

====================

The bench directory contains many testbenches to test the design.  The tests

done are VERY limited.  Some tests are self-checking and others simply

stimulates the design and the output has to be manually checked.

If you are using MS Visual Studio, there are projects files already prepared

to compile and run the testbenches.  All you have to do is update the location

of the SystemC include directory and the SystemC link library location in the

project.

If you are using GCC, I am not too familiar with the configure scripts that

search to see if SystemC is properly installed, is the correct version, etc.

etc.,  so there are no configure/makefile files ready to use out of the box.

Also, the fact that SystemC includes a "main" function often conflicts with

autoconfigure tests.  I have tried the global testbench using KDevelop and

it works perfectly.