Updated system timer logic from Bob Doiron

configs/sam4s-xplained-pro/Kconfig

@@ -10,9 +10,15 @@ config SAM4S_XPLAINED_PRO_CDCACM_DEVMINOR
 	default 0
 	depends on SAM34_UDP && USBDEV && CDCACM
 
+config SAM4S_XPLAINED_PRO_SCHED_TIMER_DEVPATH
+    string "Scheduler Timer Device Path"
+	default "/dev/tc0"
+	depends on TIMER && SYSTEMTICK_EXTCLK
+
 config SAM4S_XPLAINED_PRO_CPULOAD_TIMER_DEVPATH
     string "CPU Load Timer Device Path"
-	default "/dev/tc0"
+	default "/dev/tc1"
 	depends on TIMER && SCHED_CPULOAD && SCHED_CPULOAD_EXTCLK
 
+
 endif

configs/sam4s-xplained-pro/nsh/defconfig

@@ -212,7 +212,7 @@ CONFIG_SAM34_SMC=y
 # CONFIG_SAM34_SPI0 is not set
 # CONFIG_SAM34_SSC is not set
 CONFIG_SAM34_TC0=y
-# CONFIG_SAM34_TC1 is not set
+CONFIG_SAM34_TC1=y
 # CONFIG_SAM34_TC2 is not set
 # CONFIG_SAM34_TC3 is not set
 # CONFIG_SAM34_TC4 is not set
@@ -342,7 +342,8 @@ CONFIG_NSH_MMCSDSLOTNO=0
 # Board-Specific Options
 #
 CONFIG_SAM4S_XPLAINED_PRO_CDCACM_DEVMINOR=0
-CONFIG_SAM4S_XPLAINED_PRO_CPULOAD_TIMER_DEVPATH="/dev/tc0"
+CONFIG_SAM4S_XPLAINED_PRO_SCHED_TIMER_DEVPATH="/dev/tc0"
+CONFIG_SAM4S_XPLAINED_PRO_CPULOAD_TIMER_DEVPATH="/dev/tc1"
 
 #
 # RTOS Features
@@ -359,6 +360,7 @@ CONFIG_DISABLE_ENVIRON=y
 # Clocks and Timers
 #
 CONFIG_MSEC_PER_TICK=10
+CONFIG_SYSTEMTICK_EXTCLK=y
 # CONFIG_SYSTEM_TIME64 is not set
 # CONFIG_CLOCK_MONOTONIC is not set
 CONFIG_JULIAN_TIME=y

configs/sam4s-xplained-pro/src/sam_boot.c

@@ -92,9 +92,16 @@ void sam_boardinitialize(void)
 void board_initialize(void)
 {
 #if (defined(CONFIG_SAM34_WDT) && !defined(CONFIG_WDT_DISABLE_ON_RESET))
-  /* Enable watchdog timer kicker kernel thread. */
+  /* Configure watchdog timer and enable kicker kernel thread. */
 
   DEBUGASSERT(up_wdginitialize() >= 0);
 #endif
+
+#ifdef CONFIG_TIMER
+  /* Registers the timers and starts any async processes (which may include the scheduler) */
+
+  sam_timerinitialize();
+#endif
+
 }
 #endif /* CONFIG_BOARD_INITIALIZE */

configs/sam4s-xplained-pro/src/sam_nsh.c

@@ -151,12 +151,6 @@ int nsh_archinitialize(void)
     }
 #endif
 
-#ifdef CONFIG_TIMER
-  /* Registers the timer driver and starts an async interrupt. */
-
-  sam_timerinitialize();
-#endif
-
 #ifdef HAVE_USBMONITOR
   /* Start the USB Monitor */