diff --git a/configs/same70-xplained/README.txt b/configs/same70-xplained/README.txt index 253be2acbc4..ef2299ecfe5 100644 --- a/configs/same70-xplained/README.txt +++ b/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 diff --git a/configs/samv71-xult/README.txt b/configs/samv71-xult/README.txt index 711065f9ed0..15838ab1536 100644 --- a/configs/samv71-xult/README.txt +++ b/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 - calling sam_sckc_enable(). Otherwise, you will be doing all system - timing using the RC clock! UPDATE: This will now be selected by default - when you configure for TICKLESS support. + input. The 32.768KHz crystal is selected by the definition + BOARD_HAVE_SLOWXTAL in the configs/samv71-xult/board.h file. SAMV7 Timer Usage -----------------