---

title: “Reference Manuals”

• [Comportability Definition and Specification]({{< relref “comportability_specification” >}})
• [Device Interface Function (DIF) Specification]({{< relref “device_interface_functions” >}})
• Tool Guides
  • [Topgen Tool]({{< relref “topgen_tool” >}}): Describes topgen.py and its Hjson format source. Used to generate rtl and validation files for top specific modules such as PLIC, Pinmux and crossbar.
  • [Register Tool]({{< relref “register_tool” >}}): Describes regtool.py and its Hjson format source. Used to generate documentation, rtl, header files and validation files for IP Registers and toplevel.
  • [Ipgen Tool]({{< relref “ipgen_tool” >}}): Describes ipgen.py and its Hjson control file. Used to generate IP blocks from IP templates.
  • [Crossbar Tool]({{< relref “crossbar_tool” >}}): Describes tlgen.py and its Hjson format source. Used to generate self-documentation, rtl files of the crossbars at the toplevel.
  • [Vendor-In Tool]({{< relref “vendor_in_tool” >}}): Describes util/vendor.py and its Hjson control file. Used to pull a local copy of code maintained in other upstream repositories and apply local patch sets.
• [FPGA Reference Manual]({{< relref “ref_manual_fpga.md” >}})
• [OpenTitan Continuous Integration]({{< relref “continuous_integration.md” >}})