Altera Arria V Avalon-ST - Manual (Page 174)

Root Port Testbench
This testbench simulates up to an ×8 PCI Express link using either the PIPE interfaces of the Root Port
and Endpoints or the serial PCI Express interface. The testbench design does not allow more than one
PCI Express link to be simulated at a time. The top-level of the testbench instantiates four main modules:
• <qsys_systemname>— Name of Root Port This is the example Root Port design. For more information
about this module, refer to Root Port Design Example.
• altpcietb_bfm_ep_example_chaining_pipen1b—This is the Endpoint PCI Express mode described in
the section Chaining DMA Design Examples.
• altpcietb_pipe_phy—There are eight instances of this module, one per lane. These modules connect
the PIPE MAC layer interfaces of the Root Port and the Endpoint. The module mimics the behavior of
the PIPE PHY layer to both MAC interfaces.
• altpcietb_bfm_driver_rp—This module drives transactions to the Root Port BFM. This is the module
that you modify to vary the transactions sent to the example Endpoint design or your own design. For
more information about this module, see Test Driver Module.
The testbench has routines that perform the following tasks:
• Generates the reference clock for the Endpoint at the required frequency.
• Provides a reset at start up.
Note: Before running the testbench, you should set the following parameters:
•
serial_sim_hwtcl
: Set this parameter in <instantiation name>_tb.v . This parameter controls
whether the testbench simulates in PIPE mode or serial mode. When is set to 0, the simulation
runs in PIPE mode; when set to 1, it runs in serial mode. Although the
serial_sim_hwtcl
parameter is available in other files, if you set this parameter at the lower level, then it will get
overwritten by the tb.v level.
•
serial_sim_hwtcl
: Set to 1 for serial simulation and 0 for PIPE simulation.
•
enable_pipe32_sim_hwtcl
: Set to 0 for serial simulation and 1 for PIPE simulation.
Chaining DMA Design Examples
This design examples shows how to create a chaining DMA native Endpoint which supports simultaneous
DMA read and write transactions. The write DMA module implements write operations from the
Endpoint memory to the root complex (RC) memory. The read DMA implements read operations from
the RC memory to the Endpoint memory.
When operating on a hardware platform, the DMA is typically controlled by a software application
running on the root complex processor. In simulation, the generated testbench, along with this design
example, provides a BFM driver module in Verilog HDL that controls the DMA operations. Because the
example relies on no other hardware interface than the PCI Express link, you can use the design example
for the initial hardware validation of your system.
The design example includes the following two main components:
• The Root Port variation
• An Application Layer design example
16-4 Root Port Testbench
2014.12.15
Altera Corporation Testbench and Design Example
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