Merged glossary from prjxray wiki and tidied up some terms.

Signed-off-by: Sarah Maddox <sarahmaddox@google.com>

docs/architecture/glossary.rst

@@ -3,70 +3,132 @@ Glossary
 
 .. glossary::
 
-  basic element
   BEL
-  basic logic element
   BLE
-    For example a LUT5, LUT6, CARRY4, or MUX, but not PIPs.
+  Basic element (BEL) or basic logic element (BLE)
+    BELs or BLEs are the basic logic elements in an FPGA, including
+    carry or fast adders (CFAs), flip flops (FFs), lookup tables (LUTs),
+    multiplexers (MUXes), and other element types.
+    Note: Programmable interconnects (PIPs) are not counted as BELs.
 
-    BELs come in two types:
+    BELs come in two forms:
 
     * Basic BEL - A logic unit which does things.
-    * Routing BEL - A unit which is statically configured at the routing time.
+    * Routing BEL - A unit which is statically configured at routing time.
      
 
-  bitstream
+  Bitstream
     Binary data that is directly loaded into an FPGA to perform configuration.
     Contains configuration :term:`frames <frame>` as well as programming
     sequences and other commands required to load and activate same.
 
-  clock domain
+  Clock domain
     Portion of a :term:`horizontal clock row` to one side of the global clock
     spine. Often refers to :term:`tiles <tile>` that are associated with these
     clocks.
 
-  column
-    Collection of :term:`tiles <tile>` physically organized as a vertical line.
+  Column
+    A term used in :term:`bitstream` configuration to denote
+    a collection of :term:`tiles <tile>`, physically organized as
+    a vertical line, and configured by the same set of configuration frames.
+    Logic columns span 50 tiles vertically and 2 tiles horizontally
+    (pairs of logic tiles and interconnect tiles).
 
-  configurable logic block
   CLB
-    Basic building block of logic. 
+  Configurable logic block (CLB)
+    The configurable logic unit of an FPGA. Also called a **logic cell**.
+    A CLB is a combination of basic logic elements (:term:`BELs <BEL>`).
 
-  frame
-    Fundamental unit of configuration data consisting of 101 :term:`words <word>`.
+  Database
+    A term used in *Project X-Ray* to denote
+    text files containing meaningful labels for bit positions within
+    :term:`segments <segment>`.
 
-  half
+  Frame
+    The fundamental unit of :term:`bitstream` configuration data consisting of
+    101 :term:`words <word>`.
+    Each frame has a 32-bit frame address and 101 payload words, 32 bits each.
+    The 50th payload words is an EEC.
+    The 7 LSB bits of the frame address are the frame index within the
+    configuration :term:`column` (called *minor frame address* in the Xilinx
+    documentation). The rest of the frame address identifies the configuration
+    column (called *base frame address* in Project X-Ray nomenclature).
+
+    The bits in an individual frame are spread out over the entire column.
+    For example, in a logic column with 50 tiles, the first tile is configured
+    with the first two words in each frame, the next tile with the next two
+    words, and so on.
+    
+  Frame base address
+    The first configuration frame address for a :term:`column`. A frame base
+    address has always the 7 LSB bits cleared.
+
+  Fuzzer
+    Scripts and a makefile to generate one or more :term:`specimens <specimen>`
+    and then convert the data from those specimens into a :term:`database`.
+
+  Half
     Portion of a device defined by a virtual line dividing the two sets of global
-    clock buffers present in a device. The two halves are simply referred to as
+    clock buffers present in a device. The two halves are referred to as
     the top and bottom halves.
 
-  node
-    Collection of :term:`wires <wire>` spanning one or more tiles.
+  Node
+    A routing node on the device. A node is a collection of :term:`wires <wire>`
+    spanning one or more "tiles"term" `tiles <tile>`.
+    Nodes that are local to a tile map 1:1 to a wire. A node that spans multiple
+    tiles maps to multiple wires, one in each tile it spans.
 
-  programmable interconnect point
   PIP
+  Programmable interconnect point (PIP)
     Connection point between two wires in a tile that may be enabled or
     disabled by the configuration.
 
-  horizontal clock row
+  Horizontal clock row
     Portion of a device including 12 horizontal clocks and the 50 interconnect
     and function tiles associated with them. A :term:`half` contains one or
     more horizontal clock rows and each half may have a different number of
     rows.
+    
+  ROI
+  Region of interest (ROI)
+    A term used in *Project X-Ray* to denote a
+    rectangular region on the FPGA that is the current focus of our study.
+    Right now this is `SLICE_X12Y100:SLICE_X27Y149` on a `xc7a50tfgg484-1`
+    chip.
 
-  site
-    Portion of a tile where :term:`BELs <BEL>` can be placed.  :term:`Slices
-    <slice>` in a :term:`CLB` tile are sites.
+  Segment
+    All configuration bits for a horizontal slice of a :term:`column`.
+    This corresponds to two ranges: a range of :term:`frames <frame>`
+    and a range of :term:`words <word>` within frames. A segment of a logic
+    column is 36 frames wide and 2 words high.
 
-  slice
-    Portion of a :term:`CLB` tile that contains :term:`BELs <BEL>`.
+  Site
+    Portion of a tile where :term:`BELs <BEL>` can be placed. The
+    :term:`slices <slice>` in a :term:`CLB` tile are sites.
 
-  tile
+  Slice
+    Portion of a :term:`tile` tile that contains :term:`BELs <BEL>`.
+    A `CLBLL_L/CLBLL_R` tile contains two `SLICEL` slices.
+    A `CLBLM_L/CLBLM_R` tile contains one `SLICEL` slice and one `SLICEM` slice.
+
+  Specimen
+    A :term:`bitstream` of a (usually auto-generated) design with additional
+    files containing information about the placed and routed design.
+    These additional files are usually generated using Vivado TCL scripts
+    querying the Vivado design database.
+
+  Tile
     Fundamental unit of physical structure containing a single type of
-    resource or function.
+    resource or function. A container for :term:`sites <site>` and
+    :term:`slices <slice>`. The whole chip is a grid of tiles.
 
-  wire
+    The most important tile types are left and right interconnect tiles
+    (`INT_L` and `INT_R`) and left and right :term:`CLB` logic/memory tiles
+    (`CLBLL_L`, `CLBLL_R`, `CLBLM_L`, `CLBLM_R`).
+
+  Wire
     Physical wire within a :term:`tile`.
 
-  word
-    32-bits stored in big-endian order. Fundamental unit of :term:`bitstream` format. 
+  Word
+    32 bits stored in big-endian order. Fundamental unit of :term:`bitstream`
+    format.