Diff: mbed-os/targets/TARGET_NUVOTON/nu_timer.h

Revision:

0:8fdf9a60065b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/targets/TARGET_NUVOTON/nu_timer.h	Wed Oct 10 00:33:53 2018 +0000
@@ -0,0 +1,84 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2015-2016 Nuvoton
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef NU_TIMER_H
+#define NU_TIMER_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "cmsis.h"
+#include "ticker_api.h"
+#include "us_ticker_api.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A simple count-down timer used for Nuvoton ported drivers
+ *
+ * NOTE: nu_countdown_init must be paired with nu_countdown_free.
+ *
+ * Example:
+ * nu_countdown_ctx_s ctx;
+ * 
+ * // Set up 2 ms timeout
+ * nu_countdown_init(&ctx, 2000);
+ *
+ * // Timed-wait for a task
+ * while (true) {
+ *     // Poll the task
+ *
+ *     if (nu_countdown_expired(&ctx)) {
+ *         // Timeout
+ *     }
+ * }
+ *
+ * // Must pair nu_countdown_init with nu_countdown_free in the end
+ * nu_countdown_free(&ctx);
+ */
+
+struct nu_countdown_ctx_s {
+    const ticker_data_t *   _ticker_data;       // Hold ticker_data_t
+    us_timestamp_t          _interval_end_us;   // End of interval in us
+    bool                    _expired;           // Expired or not
+};
+
+void nu_countdown_init(struct nu_countdown_ctx_s *ctx, us_timestamp_t interval_us);
+bool nu_countdown_expired(struct nu_countdown_ctx_s *ctx);
+void nu_countdown_free(struct nu_countdown_ctx_s *ctx);
+
+
+/* Replacement for wait_us when intermediary us ticker layer is disabled
+ *
+ * Use of wait_us directly from the low power ticker causes the system to deadlock during
+ * the sleep test because the sleep test disables the intermediary us ticker layer during
+ * the test.
+ *
+ * To prevent this lockup, nu_busy_wait_us is created to replace wait_us, which uses the us ticker
+ * directly rather than go though the intermediary us ticker layer.
+ *
+ * During wait period through nu_busy_wait_us, CPU would be busy spinning. 
+ */
+void nu_busy_wait_us(uint32_t us);
+
+/* Delay 4 cycles per round by hand-counting instruction cycles */
+void nu_delay_cycle_x4(uint32_t rounds);  
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif