More work on protocol analysis page

Author: azonenberg

grapheditor.md

@@ -22,7 +22,9 @@ Right click on a block to configure it.
 
 Need a decode for an obscure or proprietary protocol that's not in the library? Build it yourself!
 
-A new filter block is a single C++ class which can chain before and after existing blocks. No need to start from raw analog samples - you can take SPI bus transactions, PCIe TLPs, or 8B/10B symbols as input. If your new decode outputs a standard data type, it can be used as input to existing library blocks as well.
+A new filter block is a single C++ class which can chain before and after existing blocks. No need to start from raw analog samples - you can take SPI bus transactions, PCIe TLPs, 8B/10B symbols, Ethernet frames, or any other supported data type as input. If your new decode outputs a standard data type, it can be used as input to existing library blocks as well.
+
+Filter blocks can be loaded from binary plugins, allowing easy distribution of filters without needing to build a custom version of libscopehal from source every time you install a new decode.
 
 The QSGMII protocol decode shown here took less than a day of engineering time to develop due to this ability to leverage existing decodes, and the [source code](https://github.com/glscopeclient/scopehal/blob/master/scopeprotocols/QSGMIIDecoder.cpp) was under 175 lines including comments. It accepts a single 5 Gbps 8B/10B stream and outputs four demuxed 1.25 Gbps 8B/10B streams which can be used as input to the existing SGMII decode.
 

images/protocol1.png

@@ -17,7 +17,9 @@ layout: default
 
 # Features
 
+* [Filter graph editor](/grapheditor)
 * [Multi-scope support](/multiscope)
+* [Protocol analysis](/protocol-analysis)
 
 # Learn more
 

images/protocol2.png

@@ -1 +1,21 @@
+---
+layout: default
+---
+
 # Protocol Analysis
+
+Combine waveform-centric and packet-centric decode views to better understand complex system behavior.
+
+In the example below, a PCIe gen2 x1 link comes up at 2.5 GT/s then negotiates a transition to 5 GT/s speed.
+
+<img src="images/protocol1.png" alt="PCIe link training protocol decode"/>
+
+Zooming in, a single TS2 training set can be seen in the waveform view, decoded at several levels. A list of packets is displayed in the protocol analyzer view below the waveform. Complex transactions or sequences of repeated packets are collapsed into a single line item unless expanded, allowing quick understanding of long captures.
+
+<img src="images/protocol2.png" alt="PCIe link training protocol decode"/>
+
+Clicking on a packet in the protocol analyzer moves the waveform view to make the packet visible, and moves the X-axis cursor (if enabled) to the start of the packet. Dragging the cursor highlights the packet under the cursor in the protocol analyzer view.
+
+The protocol analyzer view supports complex filter expressions, allowing packets of interest to be quickly located among thousands of irrelevant ones.
+
+<img src="images/protocol3.png" alt="PCIe link training protocol decode"/>