Initial Release

timer/hello_timer/hello_timer.c

@@ -0,0 +1,58 @@
+/**
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+/// \tag::timer_example[]
+volatile bool timer_fired = false;
+
+int64_t alarm_callback(alarm_id_t id, void *user_data) {
+    printf("Timer %d fired!\n", (int) id);
+    timer_fired = true;
+    // Can return a value here in us to fire in the future
+    return 0;
+}
+
+bool repeating_timer_callback(struct repeating_timer *t) {
+    printf("Repeat at %lld\n", time_us_64());
+    return true;
+}
+
+int main() {
+    stdio_init_all();
+    printf("Hello Timer!\n");
+
+    // Call alarm_callback in 2 seconds
+    add_alarm_in_ms(2000, alarm_callback, NULL, false);
+
+    // Wait for alarm callback to set timer_fired
+    while (!timer_fired) {
+        tight_loop_contents();
+    }
+
+    // Create a repeating timer that calls repeating_timer_callback.
+    // If the delay is > 0 then this is the delay between the previous callback ending and the next starting.
+    // If the delay is negative (see below) then the next call to the callback will be exactly 500ms after the
+    // start of the call to the last callback
+    struct repeating_timer timer;
+    add_repeating_timer_ms(500, repeating_timer_callback, NULL, &timer);
+    sleep_ms(3000);
+    bool cancelled = cancel_repeating_timer(&timer);
+    printf("cancelled... %d\n", cancelled);
+    sleep_ms(2000);
+
+    // Negative delay so means we will call repeating_timer_callback, and call it again
+    // 500ms later regardless of how long the callback took to execute
+    add_repeating_timer_ms(-500, repeating_timer_callback, NULL, &timer);
+    sleep_ms(3000);
+    cancelled = cancel_repeating_timer(&timer);
+    printf("cancelled... %d\n", cancelled);
+    sleep_ms(2000);
+    printf("Done\n");
+    return 0;
+}
+/// \end::timer_example[]