Update README

configs/same70-xplained/README.txt

@@ -898,6 +898,16 @@ Tickless OS
       CONFIG_SAMV7_TICKLESS_FREERUN=1  : Selects TC0 channel 1 for the free-
                                        : running timer
 
+  NOTE: In most cases, the slow clock will be used as the timer/counter
+  input.  The SAME70-Xplained board has pads for a 32.768KHz crystal,
+  however, the boad ships with that position unpopulated.  So, be default
+  this will probably end up using the slow RC oscillator which will give
+  you very bad timing.
+
+  If you add a crystal to your board, you can select to use it with the
+  definition BOARD_HAVE_SLOWXTAL in the configs/same70-xplained/board.h
+  file.
+
   SAME70 Timer Usage
   ------------------
   This current implementation uses two timers:  A one-shot timer to

configs/samv71-xult/README.txt

@@ -1471,7 +1471,7 @@ Tickless OS
   Configuration
   -------------
   The following configuration options will enable support for the Tickless
-  OS for the SAMV7 platforms using TC0 channels 0-3 (other timers or
+  OS for the SAMV7 platforms using TC0 channels 0-1 (other timers or
   timer channels could be used making the obvious substitutions):
 
     RTOS Features -> Clocks and Timers
@@ -1490,10 +1490,8 @@ Tickless OS
                                        : running timer
 
   NOTE: In most cases, the slow clock will be used as the timer/counter
-  input.  You should enable the 32.768KHz crystal for the slow clock by
+  input.  The 32.768KHz crystal is selected by the definition
-  calling sam_sckc_enable().  Otherwise, you will be doing all system
+  BOARD_HAVE_SLOWXTAL in the configs/samv71-xult/board.h file.
-  timing using the RC clock!  UPDATE: This will now be selected by default
-  when you configure for TICKLESS support.
 
   SAMV7 Timer Usage
   -----------------