Fixed bug #535.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7292 35acf78f-673a-0410-8e92-d51de3d6d3f4
doc improvement

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7293 35acf78f-673a-0410-8e92-d51de3d6d3f4
made a copy
Merge remote-tracking branch 'upstream/master'