updates
Dependencies: BLE_API mbed-dev-bin nRF51822
Fork of microbit-dal-eddystone by
DynamicPwm.cpp
00001 /* 00002 The MIT License (MIT) 00003 00004 Copyright (c) 2016 British Broadcasting Corporation. 00005 This software is provided by Lancaster University by arrangement with the BBC. 00006 00007 Permission is hereby granted, free of charge, to any person obtaining a 00008 copy of this software and associated documentation files (the "Software"), 00009 to deal in the Software without restriction, including without limitation 00010 the rights to use, copy, modify, merge, publish, distribute, sublicense, 00011 and/or sell copies of the Software, and to permit persons to whom the 00012 Software is furnished to do so, subject to the following conditions: 00013 00014 The above copyright notice and this permission notice shall be included in 00015 all copies or substantial portions of the Software. 00016 00017 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 00018 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 00019 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 00020 THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 00021 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 00022 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 00023 DEALINGS IN THE SOFTWARE. 00024 */ 00025 00026 /** 00027 * Class definition for DynamicPwm. 00028 * 00029 * This class addresses a few issues found in the underlying libraries. 00030 * This provides the ability for a neat, clean swap between PWM channels. 00031 */ 00032 00033 #include "MicroBitConfig.h" 00034 #include "DynamicPwm.h" 00035 #include "MicroBitPin.h" 00036 #include "ErrorNo.h" 00037 00038 DynamicPwm* DynamicPwm::pwms[NO_PWMS] = { NULL, NULL, NULL }; 00039 00040 uint8_t DynamicPwm::lastUsed = NO_PWMS+1; //set it to out of range i.e. 4 so we know it hasn't been used yet. 00041 00042 uint16_t DynamicPwm::sharedPeriod = 0; //set the shared period to an unknown state 00043 00044 /** 00045 * Reassigns an already operational PWM channel to the given pin. 00046 * 00047 * @param pin The desired pin to begin a PWM wave. 00048 * 00049 * @param oldPin The pin to stop running a PWM wave. 00050 * 00051 * @param channel_number The GPIOTE channel being used to drive this PWM channel 00052 * 00053 * TODO: Merge into mbed, at a later date. 00054 */ 00055 void gpiote_reinit(PinName pin, PinName oldPin, uint8_t channel_number) 00056 { 00057 // Connect GPIO input buffers and configure PWM_OUTPUT_PIN_NUMBER as an output. 00058 NRF_GPIO->PIN_CNF[pin] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos) 00059 | (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos) 00060 | (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos) 00061 | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) 00062 | (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos); 00063 00064 NRF_GPIO->OUTCLR = (1 << oldPin); 00065 NRF_GPIO->OUTCLR = (1 << pin); 00066 00067 /* Finally configure the channel as the caller expects. If OUTINIT works, the channel is configured properly. 00068 If it does not, the channel output inheritance sets the proper level. */ 00069 00070 NRF_GPIOTE->CONFIG[channel_number] = (GPIOTE_CONFIG_MODE_Task << GPIOTE_CONFIG_MODE_Pos) | 00071 ((uint32_t)pin << GPIOTE_CONFIG_PSEL_Pos) | 00072 ((uint32_t)GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos) | 00073 ((uint32_t)GPIOTE_CONFIG_OUTINIT_Low << GPIOTE_CONFIG_OUTINIT_Pos); // ((uint32_t)GPIOTE_CONFIG_OUTINIT_High << 00074 // GPIOTE_CONFIG_OUTINIT_Pos);// 00075 00076 /* Three NOPs are required to make sure configuration is written before setting tasks or getting events */ 00077 __NOP(); 00078 __NOP(); 00079 __NOP(); 00080 00081 NRF_TIMER2->CC[channel_number] = 0; 00082 } 00083 00084 /** 00085 * An internal constructor used when allocating a new DynamicPwm instance. 00086 * 00087 * @param pin the name of the pin for the pwm to target 00088 * 00089 * @param persistance the level of persistence for this pin PWM_PERSISTENCE_PERSISTENT (can not be replaced until freed, should only be used for system services really.) 00090 * or PWM_PERSISTENCE_TRANSIENT (can be replaced at any point if a channel is required.) 00091 */ 00092 DynamicPwm::DynamicPwm(PinName pin, PwmPersistence persistence) : PwmOut(pin) 00093 { 00094 this->flags = persistence; 00095 } 00096 00097 /** 00098 * Redirects the pwm channel to point at a different pin. 00099 * 00100 * @param pin the desired pin to output a PWM wave. 00101 * 00102 * @code 00103 * DynamicPwm* pwm = DynamicPwm::allocate(PinName n); 00104 * pwm->redirect(p0); // pwm is now produced on p0 00105 * @endcode 00106 */ 00107 void DynamicPwm::redirect(PinName pin) 00108 { 00109 gpiote_reinit(pin, _pwm.pin, (uint8_t)_pwm.pwm); 00110 this->_pwm.pin = pin; 00111 } 00112 00113 /** 00114 * Creates a new DynamicPwm instance, or reuses an existing instance that 00115 * has a persistence level of PWM_PERSISTENCE_TRANSIENT. 00116 * 00117 * @param pin the name of the pin for the pwm to target 00118 * 00119 * @param persistance the level of persistence for this pin PWM_PERSISTENCE_PERSISTENT (can not be replaced until freed, should only be used for system services really.) 00120 * or PWM_PERSISTENCE_TRANSIENT (can be replaced at any point if a channel is required.) 00121 * 00122 * @return a pointer to the first available free pwm channel - or the first one that can be reallocated. If 00123 * no channels are available, NULL is returned. 00124 * 00125 * @code 00126 * DynamicPwm* pwm = DynamicPwm::allocate(PinName n); 00127 * @endcode 00128 */ 00129 DynamicPwm* DynamicPwm::allocate(PinName pin, PwmPersistence persistence) 00130 { 00131 //try to find a blank spot first 00132 for(int i = 0; i < NO_PWMS; i++) 00133 { 00134 if(pwms[i] == NULL) 00135 { 00136 lastUsed = i; 00137 pwms[i] = new DynamicPwm(pin, persistence); 00138 return pwms[i]; 00139 } 00140 } 00141 00142 //no blank spot.. try to find a transient PWM 00143 int channelIterator = (lastUsed + 1 > NO_PWMS - 1) ? 0 : lastUsed + 1; 00144 00145 while(channelIterator != lastUsed) 00146 { 00147 if(pwms[channelIterator]->flags & PWM_PERSISTENCE_TRANSIENT) 00148 { 00149 lastUsed = channelIterator; 00150 pwms[channelIterator]->flags = persistence; 00151 pwms[channelIterator]->redirect(pin); 00152 return pwms[channelIterator]; 00153 } 00154 00155 channelIterator = (channelIterator + 1 > NO_PWMS - 1) ? 0 : channelIterator + 1; 00156 } 00157 00158 //if we haven't found a free one, we must try to allocate the last used... 00159 if(pwms[lastUsed]->flags & PWM_PERSISTENCE_TRANSIENT) 00160 { 00161 pwms[lastUsed]->flags = persistence; 00162 pwms[lastUsed]->redirect(pin); 00163 return pwms[lastUsed]; 00164 } 00165 00166 //well if we have no transient channels - we can't give any away! :( return null 00167 return (DynamicPwm*)NULL; 00168 } 00169 00170 /** 00171 * Frees this DynamicPwm instance for reuse. 00172 * 00173 * @code 00174 * DynamicPwm* pwm = DynamicPwm::allocate(); 00175 * pwm->release(); 00176 * @endcode 00177 */ 00178 void DynamicPwm::release() 00179 { 00180 //free the pwm instance. 00181 NRF_GPIOTE->CONFIG[(uint8_t) _pwm.pwm] = 0; 00182 pwmout_free(&_pwm); 00183 this->flags = PWM_PERSISTENCE_TRANSIENT; 00184 00185 //set the pointer to this object to null... 00186 for(int i =0; i < NO_PWMS; i++) 00187 if(pwms[i] == this) 00188 { 00189 delete pwms[i]; 00190 pwms[i] = NULL; 00191 } 00192 } 00193 00194 /** 00195 * A lightweight wrapper around the super class' write in order to capture the value 00196 * 00197 * @param value the duty cycle percentage in floating point format. 00198 * 00199 * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER if value is out of range 00200 * 00201 * @code 00202 * DynamicPwm* pwm = DynamicPwm::allocate(); 00203 * pwm->write(0.5); 00204 * @endcode 00205 */ 00206 int DynamicPwm::write(float value){ 00207 00208 if(value < 0) 00209 return MICROBIT_INVALID_PARAMETER; 00210 00211 PwmOut::write(value); 00212 lastValue = value; 00213 00214 return MICROBIT_OK; 00215 } 00216 00217 /** 00218 * Retreives the PinName associated with this DynamicPwm instance. 00219 * 00220 * @code 00221 * DynamicPwm* pwm = DynamicPwm::allocate(PinName n); 00222 * 00223 * // returns the PinName n. 00224 * pwm->getPinName(); 00225 * @endcode 00226 * 00227 * @note This should be used to check that the DynamicPwm instance has not 00228 * been reallocated for use in another part of a program. 00229 */ 00230 PinName DynamicPwm::getPinName() 00231 { 00232 return _pwm.pin; 00233 } 00234 00235 /** 00236 * Retreives the last value that has been written to this DynamicPwm instance. 00237 * in the range 0 - 1023 inclusive. 00238 * 00239 * @code 00240 * DynamicPwm* pwm = DynamicPwm::allocate(PinName n); 00241 * pwm->write(0.5); 00242 * 00243 * // will return 512. 00244 * pwm->getValue(); 00245 * @endcode 00246 */ 00247 int DynamicPwm::getValue() 00248 { 00249 return (float)lastValue * float(MICROBIT_PIN_MAX_OUTPUT); 00250 } 00251 00252 /** 00253 * Retreives the current period in use by the entire PWM module in microseconds. 00254 * 00255 * Example: 00256 * @code 00257 * DynamicPwm* pwm = DynamicPwm::allocate(PinName n); 00258 * pwm->getPeriod(); 00259 * @endcode 00260 */ 00261 int DynamicPwm::getPeriodUs() 00262 { 00263 return sharedPeriod; 00264 } 00265 00266 /** 00267 * Retreives the current period in use by the entire PWM module in milliseconds. 00268 * 00269 * Example: 00270 * @code 00271 * DynamicPwm* pwm = DynamicPwm::allocate(PinName n); 00272 * pwm->setPeriodUs(20000); 00273 * 00274 * // will return 20000 00275 * pwm->getPeriod(); 00276 * @endcode 00277 */ 00278 int DynamicPwm::getPeriod() 00279 { 00280 return getPeriodUs() / 1000; 00281 } 00282 00283 /** 00284 * Sets the period used by the WHOLE PWM module. 00285 * 00286 * @param period the desired period in microseconds. 00287 * 00288 * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER if period is out of range 00289 * 00290 * Example: 00291 * @code 00292 * DynamicPwm* pwm = DynamicPwm::allocate(PinName n); 00293 * 00294 * // period now is 20ms 00295 * pwm->setPeriodUs(20000); 00296 * @endcode 00297 * 00298 * @note Any changes to the period will AFFECT ALL CHANNELS. 00299 */ 00300 int DynamicPwm::setPeriodUs(int period) 00301 { 00302 if(period < 0) 00303 return MICROBIT_INVALID_PARAMETER; 00304 00305 //#HACK this forces mbed to update the pulse width calculation. 00306 period_us(period); 00307 write(lastValue); 00308 sharedPeriod = period; 00309 00310 return MICROBIT_OK; 00311 } 00312 00313 /** 00314 * Sets the period used by the WHOLE PWM module. Any changes to the period will AFFECT ALL CHANNELS. 00315 * 00316 * @param period the desired period in milliseconds. 00317 * 00318 * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER if period is out of range 00319 * 00320 * Example: 00321 * @code 00322 * DynamicPwm* pwm = DynamicPwm::allocate(PinName n); 00323 * 00324 * // period now is 20ms 00325 * pwm->setPeriod(20); 00326 * @endcode 00327 */ 00328 int DynamicPwm::setPeriod(int period) 00329 { 00330 return setPeriodUs(period * 1000); 00331 }
Generated on Tue Jul 12 2022 21:39:16 by 1.7.2