usrp

docs/source/eq.rst

@@ -1,5 +1,5 @@
 Sub-carrier Equalization and Pilot Correction
-============================================
+=============================================
 
 - **Module**: :file:`equalizer.v`
 - **Input**: ``I (16), Q (16)``

docs/source/index.rst

@@ -26,4 +26,5 @@ Highlights are:
    sig
    setting
    verilog
+   usrp
 

docs/source/overview.rst

@@ -110,6 +110,7 @@ a conducted or over the air setup. These files covers all the bit rates (legacy
 and HT) supported in |project|.
 
 .. _sec_sample:
+
 Sample File
 -----------
 

docs/source/sample.rst

@@ -1 +0,0 @@
-

docs/source/usrp.rst

@@ -0,0 +1,57 @@
+Integration with USRP
+=====================
+
+|project| was originally developed on Ettus Research USRP N210 platform. This
+short guide explains how to modify the USRP N210's FPGA code base to
+accommodate |project|.
+
+USRP N2x0 FPGA Overview
+-----------------------
+
+The top level model of USRP N2x0 (N200 and N210) can be found in
+:file:`top/N2x0/u2plus.v`. It instantiates the ``u2plus_core`` module, which
+contains the core modules such as the receiver and transmit chain. In
+particular, the receive chain includes ``rx_frontend``, ``ddc_chain`` and
+``vita_rx_chain``. Similarly, the transmit chain includes ``vita_tx_chain``,
+``duc_chain`` and ``tx_frontend``.
+
+The code base contains placeholder modules (``dsp_rx_glue`` and ``dsp_tx_glue``)
+for extension. These modules are controlled by Verilog compilation flags and by
+default they are simply pass-through and have no effect on the signal processing
+at all.
+
+
+Enable Custom Modules
+---------------------
+
+Take the receive chain as an example, inside ``dsp_rx_glue`` module, it checks
+the ``RX_DSP0_MODULE`` macro and instantiates it if found. The macro can be
+defined in a customized Makefile. Make a copy of the
+:file:`top/N2x0/Makefile.N210R4`, name it to
+:file:`top/N2x0/Makefile.N210R4.custom`. And then make these changes.
+
+- Change ``BUILD_DIR`` to ``$(abspath build$(ISE)-N210R4-custom)``. This will
+  create a new build directory for our custom build.
+
+- Comment out ``CUSTOM_SRCS`` and ``CUSTOM_DEFS``. We will define them in a
+  separate Makefile.
+
+- Find ``Verilog Macros`` and change it to
+  ``"LVDS=1|RX_DSP0_MODULE=custom_dsp_rx|RX_DSP1_MODULE=custom_dsp_rx|TX_DSP0_MODULE=custom_dsp_tx|TX_DSP1_MODULE=custom_dsp_tx|FIFO_CTRL_NO_TIME=1"``.
+  This defines the macros to so that the custom modules are instantiated by the
+  glue modules mentioned earlier.
+
+After these changes, the two modules in :file:`custom/custom_dsp_rx.v` and
+:file:`custom/custom_dsp_tx.v` will be instantiated. By default they are simply
+pass-through. For instance, the output of RF frontend are directly connnected to
+the input of DDC, and the output of DDC are directly connected to the VITA RX
+module.
+
+To integrate |project|, we only need to *insert* it after the DDC but before
+VITA RX module. That is, the ``sample_in/sample_in_strobe`` of the ``dot11``
+module should be connected to the ``ddc_out/ddc_out_strobe`` signal.
+
+Also note that two receive chains are defined in ``u2plus_core`` module, so that
+the two antenna ports can be configured in TX/RX or RX/RX mode. To save FPGA
+resource, you may want to comment out one of the RX chains to make more room for
+|project|.