Diff: api/DigitalOut.h

Revision:

144:ef7eb2e8f9f7

Parent:

0:9b334a45a8ff

--- a/api/DigitalOut.h	Tue Aug 02 14:07:36 2016 +0000
+++ b/api/DigitalOut.h	Fri Sep 02 15:07:44 2016 +0100
@@ -1,116 +1,126 @@
-/* mbed Microcontroller Library
- * Copyright (c) 2006-2013 ARM Limited
- *
- * 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 MBED_DIGITALOUT_H
-#define MBED_DIGITALOUT_H
-
-#include "platform.h"
-#include "gpio_api.h"
-
-namespace mbed {
-
-/** A digital output, used for setting the state of a pin
- *
- * Example:
- * @code
- * // Toggle a LED
- * #include "mbed.h"
- *
- * DigitalOut led(LED1);
- *
- * int main() {
- *     while(1) {
- *         led = !led;
- *         wait(0.2);
- *     }
- * }
- * @endcode
- */
-class DigitalOut {
-
-public:
-    /** Create a DigitalOut connected to the specified pin
-     *
-     *  @param pin DigitalOut pin to connect to
-     */
-    DigitalOut(PinName pin) : gpio() {
-        gpio_init_out(&gpio, pin);
-    }
-
-    /** Create a DigitalOut connected to the specified pin
-     *
-     *  @param pin DigitalOut pin to connect to
-     *  @param value the initial pin value
-     */
-    DigitalOut(PinName pin, int value) : gpio() {
-        gpio_init_out_ex(&gpio, pin, value);
-    }
-
-    /** Set the output, specified as 0 or 1 (int)
-     *
-     *  @param value An integer specifying the pin output value,
-     *      0 for logical 0, 1 (or any other non-zero value) for logical 1
-     */
-    void write(int value) {
-        gpio_write(&gpio, value);
-    }
-
-    /** Return the output setting, represented as 0 or 1 (int)
-     *
-     *  @returns
-     *    an integer representing the output setting of the pin,
-     *    0 for logical 0, 1 for logical 1
-     */
-    int read() {
-        return gpio_read(&gpio);
-    }
-
-    /** Return the output setting, represented as 0 or 1 (int)
-     *
-     *  @returns
-     *    Non zero value if pin is connected to uc GPIO
-     *    0 if gpio object was initialized with NC
-     */
-    int is_connected() {
-        return gpio_is_connected(&gpio);
-    }
-
-#ifdef MBED_OPERATORS
-    /** A shorthand for write()
-     */
-    DigitalOut& operator= (int value) {
-        write(value);
-        return *this;
-    }
-
-    DigitalOut& operator= (DigitalOut& rhs) {
-        write(rhs.read());
-        return *this;
-    }
-
-    /** A shorthand for read()
-     */
-    operator int() {
-        return read();
-    }
-#endif
-
-protected:
-    gpio_t gpio;
-};
-
-} // namespace mbed
-
-#endif
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * 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 MBED_DIGITALOUT_H
+#define MBED_DIGITALOUT_H
+
+#include "platform.h"
+#include "gpio_api.h"
+#include "critical.h"
+
+namespace mbed {
+
+/** A digital output, used for setting the state of a pin
+ *
+ * @Note Synchronization level: Interrupt safe
+ *
+ * Example:
+ * @code
+ * // Toggle a LED
+ * #include "mbed.h"
+ *
+ * DigitalOut led(LED1);
+ *
+ * int main() {
+ *     while(1) {
+ *         led = !led;
+ *         wait(0.2);
+ *     }
+ * }
+ * @endcode
+ */
+class DigitalOut {
+
+public:
+    /** Create a DigitalOut connected to the specified pin
+     *
+     *  @param pin DigitalOut pin to connect to
+     */
+    DigitalOut(PinName pin) : gpio() {
+        // No lock needed in the constructor
+        gpio_init_out(&gpio, pin);
+    }
+
+    /** Create a DigitalOut connected to the specified pin
+     *
+     *  @param pin DigitalOut pin to connect to
+     *  @param value the initial pin value
+     */
+    DigitalOut(PinName pin, int value) : gpio() {
+        // No lock needed in the constructor
+        gpio_init_out_ex(&gpio, pin, value);
+    }
+
+    /** Set the output, specified as 0 or 1 (int)
+     *
+     *  @param value An integer specifying the pin output value,
+     *      0 for logical 0, 1 (or any other non-zero value) for logical 1
+     */
+    void write(int value) {
+        // Thread safe / atomic HAL call
+        gpio_write(&gpio, value);
+    }
+
+    /** Return the output setting, represented as 0 or 1 (int)
+     *
+     *  @returns
+     *    an integer representing the output setting of the pin,
+     *    0 for logical 0, 1 for logical 1
+     */
+    int read() {
+        // Thread safe / atomic HAL call
+        return gpio_read(&gpio);
+    }
+
+    /** Return the output setting, represented as 0 or 1 (int)
+     *
+     *  @returns
+     *    Non zero value if pin is connected to uc GPIO
+     *    0 if gpio object was initialized with NC
+     */
+    int is_connected() {
+        // Thread safe / atomic HAL call
+        return gpio_is_connected(&gpio);
+    }
+
+    /** A shorthand for write()
+     */
+    DigitalOut& operator= (int value) {
+        // Underlying write is thread safe
+        write(value);
+        return *this;
+    }
+
+    DigitalOut& operator= (DigitalOut& rhs) {
+        core_util_critical_section_enter();
+        write(rhs.read());
+        core_util_critical_section_exit();
+        return *this;
+    }
+
+    /** A shorthand for read()
+     */
+    operator int() {
+        // Underlying call is thread safe
+        return read();
+    }
+
+protected:
+    gpio_t gpio;
+};
+
+} // namespace mbed
+
+#endif