tests/periph_rtt: added test for RTT drivers

tests/periph_rtt/Makefile

@@ -0,0 +1,10 @@
+export APPLICATION = periph_rtt
+include ../Makefile.tests_common
+
+BOARD_BLACKLIST := chronos mbed_lpc1768 msb-430 msb-430h native qemu-i386 redbee-econotag telosb \
+                   wsn430-v1_3b wsn430-v1_4 z1
+# all listed boards: no periph_conf.h defined,
+
+DISABLE_MODULE += auto_init
+
+include $(RIOTBASE)/Makefile.include

tests/periph_rtt/README.md

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+Expected result
+===============
+When everything works as expected, you should see a hello message popping up every 10 seconds.
+
+Background
+==========
+Test for the low-level RTT driver.

tests/periph_rtt/main.c

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+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup tests
+ * @{
+ *
+ * @file
+ * @brief       Test for low-level Real Time Timer drivers
+ *
+ * This test will initialize the real-time timer and trigger an alarm printing
+ * 'Hello' every 10 seconds
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+
+#include "cpu.h"
+#include "periph_conf.h"
+#include "periph/rtt.h"
+
+/* only compile this test if a RTT device is defined */
+#if RTT_NUMOF
+
+#define TICKS_TO_WAIT       (10 * RTT_FREQUENCY)
+
+void cb(void *arg)
+{
+    (void)arg;
+    uint32_t now;
+
+    now = rtt_get_counter() + TICKS_TO_WAIT;
+    now = (now > RTT_MAX_VALUE) ? now - RTT_MAX_VALUE : now;
+    rtt_set_alarm(now, cb, 0);
+    puts("Hello");
+}
+
+
+int main(void)
+{
+    puts("\nRIOT RTT low-level driver test");
+    puts("This test will display 'Hello' every 10 seconds\n");
+
+    puts("Initializing the RTT driver");
+    rtt_init();
+
+    puts("Setting initial alarm");
+    rtt_set_alarm(TICKS_TO_WAIT, cb, 0);
+
+    puts("Done setting up the RTT, wait for many Hellos");
+    return 0;
+}
+
+#else
+
+int main(void)
+{
+    puts("\nRIOT RTT low-level driver test");
+    puts("There are no RTT devices defined for this board!");
+
+    return 0;
+}
+
+#endif /* RTT_NUMOF */