boards/avsextrem: configured periph timer

boards/avsextrem/Makefile.features

 FEATURES_PROVIDED += periph_gpio
 FEATURES_PROVIDED += periph_rtc
 FEATURES_PROVIDED += periph_spi
+FEATURES_PROVIDED += periph_timer
 FEATURES_MCU_GROUP = arm7

boards/avsextrem/include/board.h

@@ -56,6 +56,11 @@ extern "C" {
 #define STDIO_RX_BUFSIZE    (64U)
 /** @} */
 
+/**
+ * @brief Deprecated HW_TIMER definition (to be removed)
+ */
+#define HW_TIMER             TIMER_DEV(0)
+
 /**
  * @brief Initialize the board's clock system
  */

boards/avsextrem/include/periph_conf.h

@@ -25,6 +25,22 @@
 extern "C" {
 #endif
 
+/**
+ * @brief   Clock configuration
+ * @{
+ */
+#define CLOCK_CORECLOCK     (72000000U)         /* this board runs with 72MHz */
+
+#define CLOCK_PCLK          (CLOCK_CORECLOCK)
+/** @} */
+
+/**
+ * @brief   Timer configuration, select a number from 1 to 4
+ * @{
+ */
+#define TIMER_NUMOF         (1U)
+/** @} */
+
 /**
  * @brief PWM device and pinout configuration
  */