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targets/TARGET_ONSEMI/TARGET_NCS36510/pwmout_api.c
- Committer:
- amithy
- Date:
- 2017-11-09
- Revision:
- 178:c26431f84b0d
- Parent:
- 153:fa9ff456f731
File content as of revision 178:c26431f84b0d:
/** ****************************************************************************** * @file pwmout_api.c * @brief Implementation of a PWM driver * @internal * @author ON Semiconductor * $Rev: * $Date: ****************************************************************************** * Copyright 2016 Semiconductor Components Industries LLC (d/b/a ON Semiconductor). * All rights reserved. This software and/or documentation is licensed by ON Semiconductor * under limited terms and conditions. The terms and conditions pertaining to the software * and/or documentation are available at http://www.onsemi.com/site/pdf/ONSEMI_T&C.pdf * (ON Semiconductor Standard Terms and Conditions of Sale, Section 8 Software) and * if applicable the software license agreement. Do not use this software and/or * documentation unless you have carefully read and you agree to the limited terms and * conditions. By using this software and/or documentation, you agree to the limited * terms and conditions. * * THIS SOFTWARE IS PROVIDED "AS IS". NO WARRANTIES, WHETHER EXPRESS, IMPLIED * OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. * ON SEMICONDUCTOR SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER. * @endinternal */ #include "pwmout_api.h" #include "PeripheralPins.h" #include "mbed_assert.h" #include "clock.h" #if DEVICE_PWMOUT /** * \defgroup hal_pwmout Pwmout hal functions * @{ */ /** Initialize the pwm out peripheral and configure the pin * * @param obj The pwmout object to initialize * @param pin The pwmout pin to initialize */ void pwmout_init(pwmout_t *obj, PinName pin) { /* Get the base address of the PWM register using the pinmap functions ; pwmout_s struct contains base address only */ PWMName pwm; pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM); MBED_ASSERT(pwm != (PWMName)NC); pinmap_pinout(pin, PinMap_PWM); obj->pwmReg = (PwmReg_pt)pwm; MBED_ASSERT(obj->pwmReg != 0x00000000); CLOCK_ENABLE(CLOCK_PWM); /* Configuration parameters of duty cycle 0x4000B000, and prescaler 0x4000B00C, shall be set to default values */ /* Duty cycle shall be 50% and prescaler shall be disabled by default */ obj->pwmReg->DUTYCYCLE = 0x80; /* Write the PWM output enable register 0x4000B004, to 1 */ obj->pwmReg->PWM_ENABLE = 0x1; obj->pwmReg->PRESCALE_DISABLE = 0x1; } /** Deinitialize the pwmout object * * @param obj The pwmout object */ void pwmout_free(pwmout_t *obj) { /* Write the PWM output disable register 0x4000B008, to 1 */ obj->pwmReg->PWM_DISABLE = 0x1; } /** Set the output duty-cycle in range <0.0f, 1.0f> * * Value 0.0f represents 0 percentage, 1.0f represents 100 percent. * @param obj The pwmout object * @param percent The floating-point percentage number */ void pwmout_write(pwmout_t *obj, float percent) { if (percent == 0.0) { obj->pwmReg->DUTYCYCLE = 0x00; } else if (percent == 1.0) { obj->pwmReg->DUTYCYCLE = 0xFF; } else { /* Write the duty cycle config register 0x4000B000, with the value passed on */ /* ((percent * 255) + 1) is the duty cycle. Plus 1 is for accounting for round off errors; like a ceil function */ obj->pwmReg->DUTYCYCLE = (uint8_t)((percent * 255) + 1); } } /** Read the current float-point output duty-cycle * * @param obj The pwmout object * @return A floating-point output duty-cycle */ float pwmout_read(pwmout_t *obj) { float retVal = 0.0; float dc = 0.0; /* Read out the value of duty cycle register 0x4000B000 and return as a percent */ /* Read value / 255 is the percent returned */ dc = obj->pwmReg->DUTYCYCLE; retVal = dc/ (float)255; return(retVal); } /** Set the PWM period specified in seconds, keeping the duty cycle the same * * Periods smaller than microseconds (the lowest resolution) are set to zero. * @param obj The pwmout object * @param seconds The floating-point seconds period */ void pwmout_period(pwmout_t *obj, float seconds) { /* Cannot be configured, prescaler is either 256 or 4096 */ return; } /** Set the PWM period specified in miliseconds, keeping the duty cycle the same * * @param obj The pwmout object * @param ms The milisecond period */ void pwmout_period_ms(pwmout_t *obj, int ms) { /* Cannot be configured, prescaler is either 256 or 4096 */ return; } /** Set the PWM period specified in microseconds, keeping the duty cycle the same * * @param obj The pwmout object * @param us The microsecond period */ void pwmout_period_us(pwmout_t *obj, int us) { /* Cannot be configured, prescaler is either 256 or 4096 */ return; } /** Set the PWM pulsewidth specified in seconds, keeping the period the same. * * @param obj The pwmout object * @param seconds The floating-point pulsewidth in seconds */ void pwmout_pulsewidth(pwmout_t *obj, float seconds) { /* Pulse width can never be in seconds since the period * itself is limited to either 8uSec or 128uSec */ return; } /** Set the PWM pulsewidth specified in miliseconds, keeping the period the same. * * @param obj The pwmout object * @param ms The floating-point pulsewidth in miliseconds */ void pwmout_pulsewidth_ms(pwmout_t *obj, int ms) { /* Pulse width can never be in seconds since the period * itself is limited to either 8uSec or 128uSec */ return; } /** Set the PWM pulsewidth specified in microseconds, keeping the period the same. * * @param obj The pwmout object * @param us The floating-point pulsewidth in microseconds */ void pwmout_pulsewidth_us(pwmout_t *obj, int us) { int pulseWidth = 0; /* Check if the uSec value is greater than 128uSec, if so reject */ if (us > 128) { return; } /* If pulsewidth is less than 128uSec, set the prescaler to 4096 * by enabling prescale register 0x4000B00C to 1 */ obj->pwmReg->PRESCALE_ENABLE = 0x1; /* Calculate the duty cycle based on the width of the pulse */ /* ((255 * us) / 128) + 1 = duty cycle */ pulseWidth = (int)((float)(255 * us)/(float)128) + 1; if (us == 0) { obj->pwmReg->DUTYCYCLE = 0x0; } else if (us == 128) { obj->pwmReg->DUTYCYCLE = 0xFF; } else { obj->pwmReg->DUTYCYCLE = (uint8_t)pulseWidth; } } /**@}*/ #endif // DEVICE_PWMOUT