DigitalInOut.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #ifndef MBED_DIGITALINOUT_H
00017 #define MBED_DIGITALINOUT_H
00018 
00019 #include "platform.h"
00020 
00021 #include "gpio_api.h"
00022 #include "critical.h"
00023 
00024 namespace mbed {
00025 
00026 /** A digital input/output, used for setting or reading a bi-directional pin
00027  *
00028  * @Note Synchronization level: Interrupt safe
00029  */
00030 class DigitalInOut {
00031 
00032 public:
00033     /** Create a DigitalInOut connected to the specified pin
00034      *
00035      *  @param pin DigitalInOut pin to connect to
00036      */
00037     DigitalInOut(PinName pin) : gpio() {
00038         // No lock needed in the constructor
00039         gpio_init_in(&gpio, pin);
00040     }
00041 
00042     /** Create a DigitalInOut connected to the specified pin
00043      *
00044      *  @param pin DigitalInOut pin to connect to
00045      *  @param direction the initial direction of the pin
00046      *  @param mode the initial mode of the pin
00047      *  @param value the initial value of the pin if is an output
00048      */
00049     DigitalInOut(PinName pin, PinDirection direction, PinMode mode, int value) : gpio() {
00050         // No lock needed in the constructor
00051         gpio_init_inout(&gpio, pin, direction, mode, value);
00052     }
00053 
00054     /** Set the output, specified as 0 or 1 (int)
00055      *
00056      *  @param value An integer specifying the pin output value,
00057      *      0 for logical 0, 1 (or any other non-zero value) for logical 1
00058      */
00059     void write(int value) {
00060         // Thread safe / atomic HAL call
00061         gpio_write(&gpio, value);
00062     }
00063 
00064     /** Return the output setting, represented as 0 or 1 (int)
00065      *
00066      *  @returns
00067      *    an integer representing the output setting of the pin if it is an output,
00068      *    or read the input if set as an input
00069      */
00070     int read() {
00071         // Thread safe / atomic HAL call
00072         return gpio_read(&gpio);
00073     }
00074 
00075     /** Set as an output
00076      */
00077     void output() {
00078         core_util_critical_section_enter();
00079         gpio_dir(&gpio, PIN_OUTPUT);
00080         core_util_critical_section_exit();
00081     }
00082 
00083     /** Set as an input
00084      */
00085     void input() {
00086         core_util_critical_section_enter();
00087         gpio_dir(&gpio, PIN_INPUT);
00088         core_util_critical_section_exit();
00089     }
00090 
00091     /** Set the input pin mode
00092      *
00093      *  @param mode PullUp, PullDown, PullNone, OpenDrain
00094      */
00095     void mode(PinMode pull) {
00096         core_util_critical_section_enter();
00097         gpio_mode(&gpio, pull);
00098         core_util_critical_section_exit();
00099     }
00100 
00101     /** Return the output setting, represented as 0 or 1 (int)
00102      *
00103      *  @returns
00104      *    Non zero value if pin is connected to uc GPIO
00105      *    0 if gpio object was initialized with NC
00106      */
00107     int is_connected() {
00108         // Thread safe / atomic HAL call
00109         return gpio_is_connected(&gpio);
00110     }
00111 
00112     /** A shorthand for write()
00113      */
00114     DigitalInOut& operator= (int value) {
00115         // Underlying write is thread safe
00116         write(value);
00117         return *this;
00118     }
00119 
00120     DigitalInOut& operator= (DigitalInOut& rhs) {
00121         core_util_critical_section_enter();
00122         write(rhs.read());
00123         core_util_critical_section_exit();
00124         return *this;
00125     }
00126 
00127     /** A shorthand for read()
00128      */
00129     operator int() {
00130         // Underlying call is thread safe
00131         return read();
00132     }
00133 
00134 protected:
00135     gpio_t gpio;
00136 };
00137 
00138 } // namespace mbed
00139 
00140 #endif