Diff: api/PwmOut.h

Revision:

9:0ce32e54c9a7

Parent:

2:143cac498751

Child:

10:3bc89ef62ce7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/api/PwmOut.h	Mon Jun 10 16:03:00 2013 +0100
@@ -0,0 +1,158 @@
+/* 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_PWMOUT_H
+#define MBED_PWMOUT_H
+
+#include "platform.h"
+
+#if DEVICE_PWMOUT
+#include "pwmout_api.h"
+
+namespace mbed {
+
+/** A pulse-width modulation digital output
+ *
+ * Example
+ * @code
+ * // Fade a led on.
+ * #include "mbed.h"
+ *
+ * PwmOut led(LED1);
+ *
+ * int main() {
+ *     while(1) {
+ *         led = led + 0.01;
+ *         wait(0.2);
+ *         if(led == 1.0) {
+ *             led = 0;
+ *         }
+ *     }
+ * }
+ * @endcode
+ *
+ * @note
+ *  On the LPC1768 and LPC2368, the PWMs all share the same
+ *  period - if you change the period for one, you change it for all.
+ *  Although routines that change the period maintain the duty cycle
+ *  for its PWM, all other PWMs will require their duty cycle to be
+ *  refreshed.
+ */
+class PwmOut {
+
+public:
+
+    /** Create a PwmOut connected to the specified pin
+     *
+     *  @param pin PwmOut pin to connect to
+     */
+    PwmOut(PinName pin) {
+        pwmout_init(&_pwm, pin);
+    }
+
+    /** Set the ouput duty-cycle, specified as a percentage (float)
+     *
+     *  @param value A floating-point value representing the output duty-cycle,
+     *    specified as a percentage. The value should lie between
+     *    0.0f (representing on 0%) and 1.0f (representing on 100%).
+     *    Values outside this range will be saturated to 0.0f or 1.0f.
+     */
+    void write(float value) {
+        pwmout_write(&_pwm, value);
+    }
+
+    /** Return the current output duty-cycle setting, measured as a percentage (float)
+     *
+     *  @returns
+     *    A floating-point value representing the current duty-cycle being output on the pin,
+     *    measured as a percentage. The returned value will lie between
+     *    0.0f (representing on 0%) and 1.0f (representing on 100%).
+     *
+     *  @note
+     *  This value may not match exactly the value set by a previous <write>.
+     */
+    float read() {
+        return pwmout_read(&_pwm);
+    }
+
+    /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
+     *
+     *  @note
+     *   The resolution is currently in microseconds; periods smaller than this
+     *   will be set to zero.
+     */
+    void period(float seconds) {
+        pwmout_period(&_pwm, seconds);
+    }
+
+    /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
+     */
+    void period_ms(int ms) {
+        pwmout_period_ms(&_pwm, ms);
+    }
+
+    /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
+     */
+    void period_us(int us) {
+        pwmout_period_us(&_pwm, us);
+    }
+
+    /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
+     */
+    void pulsewidth(float seconds) {
+        pwmout_pulsewidth(&_pwm, seconds);
+    }
+
+    /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
+     */
+    void pulsewidth_ms(int ms) {
+        pwmout_pulsewidth_ms(&_pwm, ms);
+    }
+
+    /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
+     */
+    void pulsewidth_us(int us) {
+        pwmout_pulsewidth_us(&_pwm, us);
+    }
+
+#ifdef MBED_OPERATORS
+    /** A operator shorthand for write()
+     */
+    PwmOut& operator= (float value) {
+        write(value);
+        return *this;
+    }
+
+    PwmOut& operator= (PwmOut& rhs) {
+        write(rhs.read());
+        return *this;
+    }
+
+    /** An operator shorthand for read()
+     */
+    operator float() {
+        return read();
+    }
+#endif
+
+protected:
+    pwmout_t _pwm;
+};
+
+} // namespace mbed
+
+#endif
+
+#endif