describe bus command

git-svn-id: https://urjtag.svn.sourceforge.net/svnroot/urjtag/trunk@1482 b68d4a1b-bc3d-0410-92ed-d4ac073336b7

jtag/ChangeLog

@@ -1,5 +1,7 @@
 2009-04-08  Arnim Laeuger  <arniml>
 
+  * doc/UrJTAG.txt: describe bus command
+
   * doc/bsdl2jtag.1, doc/jtag.1, THANKS: Various manpage updates (Uwe Hermann)
 
 2009-04-06  Arnim Laeuger  <arniml>
@@ -24,7 +26,7 @@
 
 2009-03-30  Arnim Laeuger  <arniml>
 
-  * UrJTAG.txt: multi-byte description
+  * doc/UrJTAG.txt: multi-byte description
 
   * configure.ac: better description for flash-multi-byte
 

jtag/doc/UrJTAG.txt

@@ -825,6 +825,12 @@ Some chips don't allow direct access to their pins via BSR at all. For these,
 writing a new bus driver that utilizes a debug module to upload specific code
 to access the bus is inevitable.
 
+===== bus =====
+
+It's possible to initialize more than one bus for part(s) within a chain. The
+"bus" command allows to select the active bus for readmem, flashmem,
+etc. operation.
+
 ==== Part definition commands ====
 
 The following commands are also used in the data files to define a device (IC)