It appears this link at atmel.com has been taken down without what appears a replacement, so I applied the patch below.
Denis, if you have a new reference, happy to add that, of course. Gerald Index: readings.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/readings.html,v retrieving revision 1.289 diff -u -r1.289 readings.html --- readings.html 4 Mar 2018 10:02:19 -0000 1.289 +++ readings.html 10 Mar 2018 16:10:22 -0000 @@ -88,7 +88,6 @@ <li>AVR <br />Manufacturer: Atmel - <br /><a href="http://www.atmel.com/products/microcontrollers/avr/">AVR Documentation</a> </li> <li>Blackfin