diff --git a/arch/arm/src/arm/up_vectors.S b/arch/arm/src/arm/up_vectors.S
index bcf9c37d0f3..043516a50dd 100644
--- a/arch/arm/src/arm/up_vectors.S
+++ b/arch/arm/src/arm/up_vectors.S
@@ -139,7 +139,7 @@ up_vectorirq:
 	bl	up_decodeirq		/* Call the handler */
 #endif
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 .Lnoirqset:
 	ldr	r0, [sp, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr	spsr, r0
@@ -192,7 +192,7 @@ up_vectorswi:
 	mov	r0, sp			/* Get r0=xcp */
 	bl	up_syscall		/* Call the handler */
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 
 	ldr	r0, [sp, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr	spsr, r0
@@ -263,7 +263,7 @@ up_vectordata:
 #endif
 	bl	up_dataabort		/* Call the handler */
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 
 	ldr	r0, [sp, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr	spsr_cxsf, r0
@@ -333,7 +333,7 @@ up_vectorprefetch:
 	mov	r0, sp			/* Get r0=xcp */
 	bl	up_prefetchabort	/* Call the handler */
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 
 	ldr	r0, [sp, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr	spsr_cxsf, r0
@@ -400,7 +400,7 @@ up_vectorundefinsn:
 	mov	r0, sp			/* Get r0=xcp */
 	bl	up_undefinedinsn	/* Call the handler */
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 
 	ldr	r0, [sp, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr	spsr_cxsf, r0
diff --git a/arch/arm/src/armv7-a/arm.h b/arch/arm/src/armv7-a/arm.h
index 8afe1606140..3257f4de686 100644
--- a/arch/arm/src/armv7-a/arm.h
+++ b/arch/arm/src/armv7-a/arm.h
@@ -57,7 +57,7 @@
 
 /* PSR bits */
 
-#define PSR_MODE_SHIFT    (1)       /* Bits 0-4: Mode fields */
+#define PSR_MODE_SHIFT    (0)       /* Bits 0-4: Mode fields */
 #define PSR_MODE_MASK     (31 << PSR_MODE_SHIFT)
 #  define PSR_MODE_USR    (16 << PSR_MODE_SHIFT) /* User mode */
 #  define PSR_MODE_FIQ    (17 << PSR_MODE_SHIFT) /* FIQ mode */
diff --git a/arch/arm/src/armv7-a/arm_vectors.S b/arch/arm/src/armv7-a/arm_vectors.S
index 0c91139b07c..b1ff40f25ba 100644
--- a/arch/arm/src/armv7-a/arm_vectors.S
+++ b/arch/arm/src/armv7-a/arm_vectors.S
@@ -215,7 +215,7 @@ arm_vectorswi:
 	 * context switch is required.
 	 */
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 
 	ldr		r1, [r0, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr		spsr, r1
@@ -294,7 +294,7 @@ arm_vectordata:
 	 * context switch is required.
 	 */
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 
 	ldr		r1, [r0, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr		spsr_cxsf, r1
@@ -376,7 +376,7 @@ arm_vectorprefetch:
 	 * context switch is required.
 	 */
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 
 	ldr		r1, [r0, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr		spsr_cxsf, r1
@@ -453,7 +453,7 @@ arm_vectorundefinsn:
 	 * context switch is required.
 	 */
 
-	/* Restore the CPSR, SVC modr registers and return */
+	/* Restore the CPSR, SVC mode registers and return */
 
 	ldr		r1, [r0, #(4*REG_CPSR)]	/* Setup the SVC mode SPSR */
 	msr		spsr_cxsf, r1
diff --git a/arch/arm/src/sama5/sam_timerisr.c b/arch/arm/src/sama5/sam_timerisr.c
index 6ba87074c55..c048713216a 100644
--- a/arch/arm/src/sama5/sam_timerisr.c
+++ b/arch/arm/src/sama5/sam_timerisr.c
@@ -48,6 +48,7 @@
 #include <arch/board/board.h>
 
 #include "up_arch.h"
+#include "sam_periphclks.h"
 #include "chip/sam_pit.h"
 
 /****************************************************************************
@@ -100,23 +101,23 @@
 
 int up_timerisr(int irq, uint32_t *regs)
 {
-   /* "When CPIV and PICNT values are obtained by reading the Periodic
-    *  Interval Value Register (PIT_PIVR), the overflow counter (PICNT) is
-    *  reset and the PITS is cleared, thus acknowledging the interrupt. The
-    *  value of PICNT gives the number of periodic intervals elapsed since the
-    *  last read of PIT_PIVR.
-    */
+  /* "When CPIV and PICNT values are obtained by reading the Periodic
+   *  Interval Value Register (PIT_PIVR), the overflow counter (PICNT) is
+   *  reset and the PITS is cleared, thus acknowledging the interrupt. The
+   *  value of PICNT gives the number of periodic intervals elapsed since the
+   *  last read of PIT_PIVR.
+   */
 
-   uint32_t picnt = getreg32(SAM_PIT_PIVR) >> PIT_PICNT_SHIFT;
+  uint32_t picnt = getreg32(SAM_PIT_PIVR) >> PIT_PICNT_SHIFT;
 
-   /* Process timer interrupt (multiple times if we missed an interrupt) */
+  /* Process timer interrupt (multiple times if we missed an interrupt) */
 
-   while (picnt-- > 0)
-     {
-       sched_process_timer();
-     }
+  while (picnt-- > 0)
+    {
+      sched_process_timer();
+    }
 
-   return OK;
+  return OK;
 }
 
 /****************************************************************************
@@ -132,6 +133,10 @@ void up_timerinit(void)
 {
   uint32_t regval;
 
+  /* Enable the PIT peripheral */
+
+  sam_pit_enableclk();
+
   /* Make sure that interrupts from the PIT are disabled */
 
   up_disable_irq(SAM_IRQ_PIT);