tests/periph_rtt: add test for tick conversions

tests/periph_rtt/main.c

@@ -33,6 +33,8 @@
 
 static volatile uint32_t last;
 
+static const uint32_t _ticktest[] = { 1, 256, 65536, 16777216, 2147483648 };
+
 void cb(void *arg)
 {
     (void)arg;
@@ -47,11 +49,29 @@ void cb(void *arg)
 int main(void)
 {
     puts("\nRIOT RTT low-level driver test");
-    puts("This test will display 'Hello' every 5 seconds\n");
+
+    puts("RTT configuration:");
+    printf("RTT_MAX_VALUE: 0x%08x\n", (unsigned)RTT_MAX_VALUE);
+    printf("RTT_FREQUENCY: %u\n\n", (unsigned)RTT_FREQUENCY);
+
+    puts("Testing the tick conversion");
+    for (unsigned i = 0; i < ARRAY_SIZE(_ticktest); i++) {
+        uint32_t sec = RTT_TICKS_TO_SEC(_ticktest[i]);
+        uint32_t ticks = RTT_SEC_TO_TICKS(sec);
+        printf("Trying to convert %" PRIu32 " to seconds and back\n",
+               _ticktest[i]);
+        /* account for rounding errors... */
+        if ((ticks != 0) && (ticks != _ticktest[i])) {
+            puts("error: TICK conversion not working as expected\n");
+            return 1;
+        }
+    }
+    puts("All ok\n");
 
     puts("Initializing the RTT driver");
     rtt_init();
 
+    puts("This test will now display 'Hello' every 5 seconds\n");
     uint32_t now = rtt_get_counter();
     printf("RTT now: %" PRIu32 "\n", now);
 

tests/periph_rtt/tests/01-run.py

@@ -16,9 +16,12 @@
 
 
 def testfunc(child):
-    child.expect(r'This test will display \'Hello\' every (\d+) seconds')
-    period = int(child.match.group(1))
+    child.expect_exact('Testing the tick conversion')
+    child.expect_exact('All ok')
+
     child.expect_exact('Initializing the RTT driver')
+    child.expect(r'This test will now display \'Hello\' every (\d+) seconds')
+    period = int(child.match.group(1))
     child.expect(r'RTT now: \d+')
     child.expect(r'Setting initial alarm to now \+ {} s \(\d+\)'
                  .format(period))