Diff: mbed-os/drivers/DigitalIn.h

Revision:

0:9fca2b23d0ba

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/drivers/DigitalIn.h	Sat Feb 23 12:13:36 2019 +0000
@@ -0,0 +1,118 @@
+/* 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_DIGITALIN_H
+#define MBED_DIGITALIN_H
+
+#include "platform/platform.h"
+
+#include "hal/gpio_api.h"
+#include "platform/mbed_critical.h"
+
+namespace mbed {
+/** \addtogroup drivers */
+
+/** A digital input, used for reading the state of a pin
+ *
+ * @note Synchronization level: Interrupt safe
+ *
+ * Example:
+ * @code
+ * // Flash an LED while a DigitalIn is true
+ *
+ * #include "mbed.h"
+ *
+ * DigitalIn enable(p5);
+ * DigitalOut led(LED1);
+ *
+ * int main() {
+ *     while(1) {
+ *         if(enable) {
+ *             led = !led;
+ *         }
+ *         wait(0.25);
+ *     }
+ * }
+ * @endcode
+ * @ingroup drivers
+ */
+class DigitalIn {
+
+public:
+    /** Create a DigitalIn connected to the specified pin
+     *
+     *  @param pin DigitalIn pin to connect to
+     */
+    DigitalIn(PinName pin) : gpio() {
+        // No lock needed in the constructor
+        gpio_init_in(&gpio, pin);
+    }
+
+    /** Create a DigitalIn connected to the specified pin
+     *
+     *  @param pin DigitalIn pin to connect to
+     *  @param mode the initial mode of the pin
+     */
+    DigitalIn(PinName pin, PinMode mode) : gpio() {
+        // No lock needed in the constructor
+        gpio_init_in_ex(&gpio, pin, mode);
+    }
+    /** Read the input, represented as 0 or 1 (int)
+     *
+     *  @returns
+     *    An integer representing the state of the input pin,
+     *    0 for logical 0, 1 for logical 1
+     */
+    int read() {
+        // Thread safe / atomic HAL call
+        return gpio_read(&gpio);
+    }
+
+    /** Set the input pin mode
+     *
+     *  @param pull PullUp, PullDown, PullNone, OpenDrain
+     */
+    void mode(PinMode pull) {
+        core_util_critical_section_enter();
+        gpio_mode(&gpio, pull);
+        core_util_critical_section_exit();
+    }
+
+    /** 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);
+    }
+
+    /** An operator shorthand for read()
+     * \sa DigitalIn::read()
+     */
+    operator int() {
+        // Underlying read is thread safe
+        return read();
+    }
+
+protected:
+    gpio_t gpio;
+};
+
+} // namespace mbed
+
+#endif