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Diffstat (limited to 'mbed/drivers/PwmOut.h')
| -rw-r--r-- | mbed/drivers/PwmOut.h | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/mbed/drivers/PwmOut.h b/mbed/drivers/PwmOut.h new file mode 100644 index 0000000..9478167 --- /dev/null +++ b/mbed/drivers/PwmOut.h @@ -0,0 +1,185 @@ +/* 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/platform.h"
+
+#if DEVICE_PWMOUT
+#include "hal/pwmout_api.h"
+#include "platform/mbed_critical.h"
+
+namespace mbed {
+/** \addtogroup drivers */
+/** @{*/
+
+/** A pulse-width modulation digital output
+ *
+ * @Note Synchronization level: Interrupt safe
+ *
+ * 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) {
+ core_util_critical_section_enter();
+ pwmout_init(&_pwm, pin);
+ core_util_critical_section_exit();
+ }
+
+ /** 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) {
+ core_util_critical_section_enter();
+ pwmout_write(&_pwm, value);
+ core_util_critical_section_exit();
+ }
+
+ /** 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() {
+ core_util_critical_section_enter();
+ float val = pwmout_read(&_pwm);
+ core_util_critical_section_exit();
+ return val;
+ }
+
+ /** 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) {
+ core_util_critical_section_enter();
+ pwmout_period(&_pwm, seconds);
+ core_util_critical_section_exit();
+ }
+
+ /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
+ */
+ void period_ms(int ms) {
+ core_util_critical_section_enter();
+ pwmout_period_ms(&_pwm, ms);
+ core_util_critical_section_exit();
+ }
+
+ /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
+ */
+ void period_us(int us) {
+ core_util_critical_section_enter();
+ pwmout_period_us(&_pwm, us);
+ core_util_critical_section_exit();
+ }
+
+ /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
+ */
+ void pulsewidth(float seconds) {
+ core_util_critical_section_enter();
+ pwmout_pulsewidth(&_pwm, seconds);
+ core_util_critical_section_exit();
+ }
+
+ /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
+ */
+ void pulsewidth_ms(int ms) {
+ core_util_critical_section_enter();
+ pwmout_pulsewidth_ms(&_pwm, ms);
+ core_util_critical_section_exit();
+ }
+
+ /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
+ */
+ void pulsewidth_us(int us) {
+ core_util_critical_section_enter();
+ pwmout_pulsewidth_us(&_pwm, us);
+ core_util_critical_section_exit();
+ }
+
+ /** A operator shorthand for write()
+ */
+ PwmOut& operator= (float value) {
+ // Underlying call is thread safe
+ write(value);
+ return *this;
+ }
+
+ PwmOut& operator= (PwmOut& rhs) {
+ // Underlying call is thread safe
+ write(rhs.read());
+ return *this;
+ }
+
+ /** An operator shorthand for read()
+ */
+ operator float() {
+ // Underlying call is thread safe
+ return read();
+ }
+
+protected:
+ pwmout_t _pwm;
+};
+
+} // namespace mbed
+
+#endif
+
+#endif
+
+/** @}*/
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