boards/slstk3402a: add TIMER0 as second timer

This moves LETIMER0 to index 2.

boards/slstk3402a/include/board.h

@@ -37,7 +37,7 @@ extern "C" {
  * @{
  */
 #if IS_ACTIVE(CONFIG_EFM32_XTIMER_USE_LETIMER)
-#define XTIMER_DEV          (TIMER_DEV(1))
+#define XTIMER_DEV          (TIMER_DEV(2))
 #define XTIMER_HZ           (32768UL)
 #define XTIMER_WIDTH        (16)
 #else

boards/slstk3402a/include/periph_conf.h

@@ -132,8 +132,7 @@ static const spi_dev_t spi_config[] = {
 /**
  * @name    Timer configuration
  *
- * The implementation can use one low-energy timer
+ * The implementation uses two timers in cascade mode.
- * or two regular timers in cascade mode.
  * @{
  */
 static const timer_conf_t timer_config[] = {
@@ -147,7 +146,19 @@ static const timer_conf_t timer_config[] = {
             .cmu = cmuClock_WTIMER1
         },
         .irq = WTIMER1_IRQn,
-        .channel_numof = 3
+        .channel_numof = 4
+    },
+    {
+        .prescaler = {
+            .dev = TIMER0,
+            .cmu = cmuClock_TIMER0
+        },
+        .timer = {
+            .dev = TIMER1,
+            .cmu = cmuClock_TIMER1
+        },
+        .irq = TIMER1_IRQn,
+        .channel_numof = 4
     },
     {
         .prescaler = {
@@ -160,13 +171,13 @@ static const timer_conf_t timer_config[] = {
         },
         .irq = LETIMER0_IRQn,
         .channel_numof = 2
-    },
+    }
 };
 
-#define TIMER_0_ISR         isr_wtimer1
-#define TIMER_1_ISR         isr_letimer0
-
 #define TIMER_NUMOF         ARRAY_SIZE(timer_config)
+#define TIMER_0_ISR         isr_wtimer1
+#define TIMER_1_ISR         isr_timer1
+#define TIMER_2_ISR         isr_letimer0
 /** @} */
 
 /**