182 lines
8.1 KiB
C
182 lines
8.1 KiB
C
/*
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* Copyright (c) 2015, Zolertia - http://www.zolertia.com
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*---------------------------------------------------------------------------*/
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/**
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* \addtogroup cc2538
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* @{
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*
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* \defgroup cc2538-pwm-driver CC2538 PWM driver
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*
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* Driver for the CC2538 PWM on GPTIMER
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*
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* The driver uses the timers A and B of the general purpose timers to create
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* a PWM signal, allowing to set a duty cycle value from 1-100%. This
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* implementation relies on having a peripheral clock of 16MHz, but it can be
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* easily changed (see PWM_FREQ_MIN and PWM_FREQ_MAX values). The reason it is
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* fixed to these frequencies is to have a consistent duty cycle
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* implementation.
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*
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* Depending on the specific needs these limits can be changed to meet a given
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* duty cycle and lower frequencies by using the prescaler (GPTIMER_TnPR).
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*
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* The PWM timer is stopped when dropping below PM0, alternatively you can set
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* LPM_CONF_MAX_PM to zero, or call lpm_max_pm(0)
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*
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* @{
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*
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* \file
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* Header file for the CC2538 PWM driver
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*
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* \author
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* Javier Sanchez <jsanchez@zolertia.com>
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* Antonio Lignan <alinan@zolertia.com>
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*/
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/*---------------------------------------------------------------------------*/
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#ifndef PWM_H_
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#define PWM_H_
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/*---------------------------------------------------------------------------*/
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#include "contiki.h"
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#include "dev/ioc.h"
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#include "dev/gpio.h"
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#include "dev/sys-ctrl.h"
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/*---------------------------------------------------------------------------*/
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/** \name PWM return values
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* @{
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*/
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#define PWM_SUCCESS 0
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#define PWM_ERROR (-1)
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/** @} */
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/*---------------------------------------------------------------------------*/
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/** \name PWM recommended values respect to peripheral clock frequency
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* @{
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*/
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/* Roughly 244 Hz with a 16 MHz IO clock, no prescaler */
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#define PWM_SYS_IO_16MHZ_NO_PRES_MIN 0xFFFF
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#define PWM_SYS_IO_16MHZ_NO_PRES_MIN_FREQ 244
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/* Roughly 1 Hz with a 16 MHz IO clock, to keep frequency parameter in Hz */
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#define PWM_SYS_IO_16MHZ_PRES_MIN 0x00F42400
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#define PWM_SYS_IO_16MHZ_PRES_MIN_FREQ 1
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/* Yields 160 KHz at 16 MHz and allows down to 1% (integer) duty cycles */
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#define PWM_SYS_IO_16MHZ_NO_PRES_MAX 100
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#define PWM_SYS_IO_16MHZ_NO_PRES_MAX_FREQ 160000
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/** @} */
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/*---------------------------------------------------------------------------*/
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/** \name PWM driver definitions and configuration values
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* @{
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*/
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#define PWM_TIMER_A 0
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#define PWM_TIMER_B 1
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#define PWM_TIMER_0 0
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#define PWM_TIMER_1 1
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#define PWM_TIMER_2 2
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#define PWM_TIMER_3 3
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#define PWM_TIMER_MIN PWM_TIMER_0
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#define PWM_TIMER_MAX PWM_TIMER_3
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#define PWM_SIGNAL_STRAIGHT 1
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#define PWM_SIGNAL_INVERTED 0
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#define PWM_OFF_WHEN_STOP 0
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#define PWM_ON_WHEN_STOP 1
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#define PWM_GPTIMER_CFG_SPLIT_MODE 0x04
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#define PWM_DUTY_MAX 100
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#define PWM_DUTY_MIN 0
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#define PWM_FREQ_MIN PWM_SYS_IO_16MHZ_PRES_MIN_FREQ
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#define PWM_FREQ_MAX PWM_SYS_IO_16MHZ_NO_PRES_MAX_FREQ
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/** @} */
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/*---------------------------------------------------------------------------*/
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/** \name PWM functions
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* @{
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*/
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/** \brief Configures the general purpose timer in PWM mode
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* \param freq PWM frequency (in Hz)
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* \param duty PWM duty cycle (percentage in integers)
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* \param timer General purpose timer to use [0-3]
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* \param ab Select which timer to use (Timer A or B)
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* \return \c PWM_SUCCESS if successful, else \c PWM_ERROR
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*/
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int8_t pwm_enable(uint32_t freq, uint8_t duty, uint8_t timer, uint8_t ab);
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/*---------------------------------------------------------------------------*/
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/** \brief Disables a previously PWM configured GPTn
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* \param timer General purpose timer to disable [0-3]
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* \param ab Select which timer to disable (Timer A or B)
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* \param port Port number used as PWM to disable (set as input GPIO)
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* \param pin Pin number used as PWM to disable (set as input GPIO)
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* \return \c PWM_SUCCESS if successful, else \c PWM_ERROR
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*
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* This function disables a specific timer (A or B) and reset related registers
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* to default values. The user must explicitely pass the port/pin number of
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* the pin to disable as PWM and to be configured as input GPIO.
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* The module clock is not disabled with this function
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*/
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int8_t pwm_disable(uint8_t timer, uint8_t ab, uint8_t port, uint8_t pin);
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/*---------------------------------------------------------------------------*/
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/** \brief Once configured, starts the PWM
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* \param timer General purpose timer to start [0-3]
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* \param ab Select which timer to start (Timer A or B)
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* \param port Port number to use as PWM
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* \param pin Pin number to use as PWM
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* \return \c PWM_SUCCESS if successful, else \c PWM_ERROR
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*/
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int8_t pwm_start(uint8_t timer, uint8_t ab, uint8_t port, uint8_t pin);
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/*---------------------------------------------------------------------------*/
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/** \brief Halts the PWM in a given GPT/timer
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* \param timer General purpose timer to stop [0-3]
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* \param ab Select which timer to stop (Timer A or B)
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* \param port Port of the gpio port mapped to the PWM to stop
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* \param pin Pin of the gpio port mapped to the PWM to stop
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* \param state State to leave the pin once stopped, on (1) or off (0)
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* \return \c PWM_SUCCESS if successful, else \c PWM_ERROR
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*/
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int8_t pwm_stop(uint8_t timer, uint8_t ab, uint8_t port, uint8_t pin, uint8_t state);
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/*---------------------------------------------------------------------------*/
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/** \brief Sets the PWM duty cycle signal direction (high/low)
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* \param timer General purpose timer [0-3]
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* \param ab Select which timer to use (Timer A or B)
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* \param dir Direction of the PWM signal, \c PWM_SIGNAL_INVERTED or
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* \c PWM_SIGNAL_STRAIGHT
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* \return \c PWM_SUCCESS if successful, else \c PWM_ERROR
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*/
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int8_t pwm_set_direction(uint8_t timer, uint8_t ab, uint8_t dir);
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/*---------------------------------------------------------------------------*/
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/** \brief Toggle the PWM signal direction (inverts the current duty cycle)
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* \param timer General purpose timer to use [0-3]
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* \param ab Select which timer to use (Timer A or B)
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* \return \c PWM_SUCCESS if successful, else \c PWM_ERROR
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*/
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int8_t pwm_toggle_direction(uint8_t timer, uint8_t ab);
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/*---------------------------------------------------------------------------*/
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/** @} */
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#endif /* PWM_H_ */
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/*---------------------------------------------------------------------------*/
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/**
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* @}
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* @}
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*/
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