/* * Copyright (C) 2014 Freie Universität Berlin * Copyright (C) 2014 PHYTEC Messtechnik GmbH * Copyright (C) 2015-2016 Eistec AB * * This file is subject to the terms and conditions of the GNU Lesser General * Public License v2.1. See the file LICENSE in the top level directory for more * details. */ /** * @ingroup cpu_kinetis_common_pwm * * @{ * * @file * @brief Low-level PWM driver implementation * * @author Hauke Petersen * @author Johann Fischer * @author Jonas Remmert * @author Joakim Nohlgård * * @} */ #include #include #include "cpu.h" #include "periph/pwm.h" #include "periph_conf.h" /* FTM channel look up tables */ #if PWM_0_EN static const uint8_t ftm0chan[] = { #if PWM_0_CHANNELS > 0 PWM_0_CH0_FTMCHAN, #endif #if PWM_0_CHANNELS > 1 PWM_0_CH1_FTMCHAN, #endif #if PWM_0_CHANNELS > 2 PWM_0_CH2_FTMCHAN, #endif #if PWM_0_CHANNELS > 3 PWM_0_CH3_FTMCHAN, #endif #if PWM_0_CHANNELS > 4 PWM_0_CH4_FTMCHAN, #endif #if PWM_0_CHANNELS > 5 PWM_0_CH5_FTMCHAN, #endif #if PWM_0_CHANNELS > 6 PWM_0_CH6_FTMCHAN, #endif #if PWM_0_CHANNELS > 7 PWM_0_CH7_FTMCHAN, #endif }; #endif #if PWM_1_EN static const uint8_t ftm1chan[] = { #if PWM_1_CHANNELS > 0 PWM_1_CH0_FTMCHAN, #endif #if PWM_1_CHANNELS > 1 PWM_1_CH1_FTMCHAN, #endif #if PWM_1_CHANNELS > 2 PWM_1_CH2_FTMCHAN, #endif #if PWM_1_CHANNELS > 3 PWM_1_CH3_FTMCHAN, #endif #if PWM_1_CHANNELS > 4 PWM_1_CH4_FTMCHAN, #endif #if PWM_1_CHANNELS > 5 PWM_1_CH5_FTMCHAN, #endif #if PWM_1_CHANNELS > 6 PWM_1_CH6_FTMCHAN, #endif #if PWM_1_CHANNELS > 7 PWM_1_CH7_FTMCHAN, #endif }; #endif uint32_t pwm_init(pwm_t dev, pwm_mode_t mode, uint32_t freq, uint16_t res) { FTM_Type *ftm; int channels = 0; uint32_t pwm_clk = 0; const uint8_t *ftmchan = NULL; switch (dev) { #if PWM_0_EN case PWM_0: channels = PWM_0_CHANNELS; pwm_clk = PWM_0_CLK; ftm = PWM_0_DEV; ftmchan = &ftm0chan[0]; break; #endif #if PWM_1_EN case PWM_1: channels = PWM_1_CHANNELS; pwm_clk = PWM_1_CLK; ftm = PWM_1_DEV; ftmchan = &ftm1chan[0]; break; #endif default: return 0; } switch (mode) { case PWM_LEFT: case PWM_RIGHT: case PWM_CENTER: break; default: return 0; } if ((unsigned int)res > (PWM_MAX_VALUE + 1) || (res * freq) > pwm_clk) { return 0; } /* Try to find a good prescaler value */ /* The prescaler divides the module clock by a power of two, between 2^0 and 2^7 */ uint8_t prescaler = 0; /* (resolution * frequency) is the number of timer ticks per second */ while ((pwm_clk >> prescaler) > (res * freq)) { ++prescaler; if (prescaler > 7) { /* Module clock is too fast to reach the requested frequency using the * hardware supported prescaler values */ /* Note: The frequency might be reachable if the requested resolution * is increased. */ return 0; } } /* The chosen prescaler yields a timer frequency which is the * nearest possible frequency less than the requested frequency */ /* Turn on the peripheral */ pwm_poweron(dev); switch (dev) { #if PWM_0_EN case PWM_0: #if PWM_0_CHANNELS > 0 gpio_init_port(PWM_0_CH0_GPIO, PORT_PCR_MUX(PWM_0_CH0_AF)); #endif #if PWM_0_CHANNELS > 1 gpio_init_port(PWM_0_CH1_GPIO, PORT_PCR_MUX(PWM_0_CH1_AF)); #endif #if PWM_0_CHANNELS > 2 gpio_init_port(PWM_0_CH2_GPIO, PORT_PCR_MUX(PWM_0_CH2_AF)); #endif #if PWM_0_CHANNELS > 3 gpio_init_port(PWM_0_CH3_GPIO, PORT_PCR_MUX(PWM_0_CH3_AF)); #endif #if PWM_0_CHANNELS > 4 gpio_init_port(PWM_0_CH4_GPIO, PORT_PCR_MUX(PWM_0_CH4_AF)); #endif #if PWM_0_CHANNELS > 5 gpio_init_port(PWM_0_CH5_GPIO, PORT_PCR_MUX(PWM_0_CH5_AF)); #endif #if PWM_0_CHANNELS > 6 gpio_init_port(PWM_0_CH6_GPIO, PORT_PCR_MUX(PWM_0_CH6_AF)); #endif #if PWM_0_CHANNELS > 7 gpio_init_port(PWM_0_CH7_GPIO, PORT_PCR_MUX(PWM_0_CH7_AF)); #endif break; #endif #if PWM_1_EN case PWM_1: #if PWM_1_CHANNELS > 0 gpio_init_port(PWM_1_CH0_GPIO, PORT_PCR_MUX(PWM_1_CH0_AF)); #endif #if PWM_1_CHANNELS > 1 gpio_init_port(PWM_1_CH1_GPIO, PORT_PCR_MUX(PWM_1_CH1_AF)); #endif #if PWM_1_CHANNELS > 2 gpio_init_port(PWM_1_CH2_GPIO, PORT_PCR_MUX(PWM_1_CH2_AF)); #endif #if PWM_1_CHANNELS > 3 gpio_init_port(PWM_1_CH3_GPIO, PORT_PCR_MUX(PWM_1_CH3_AF)); #endif #if PWM_1_CHANNELS > 4 gpio_init_port(PWM_1_CH4_GPIO, PORT_PCR_MUX(PWM_1_CH4_AF)); #endif #if PWM_1_CHANNELS > 5 gpio_init_port(PWM_1_CH5_GPIO, PORT_PCR_MUX(PWM_1_CH5_AF)); #endif #if PWM_1_CHANNELS > 6 gpio_init_port(PWM_1_CH6_GPIO, PORT_PCR_MUX(PWM_1_CH6_AF)); #endif #if PWM_1_CHANNELS > 7 gpio_init_port(PWM_1_CH7_GPIO, PORT_PCR_MUX(PWM_1_CH7_AF)); #endif break; #endif default: return 0; } /* disable write protect for changing settings */ ftm->MODE = FTM_MODE_WPDIS_MASK; /* reset timer match value */ for (int i = 0; i < channels; i++) { ftm->CONTROLS[i].CnV = 0; } /* reset timer configuration registers */ ftm->COMBINE = 0; ftm->CNTIN = 0; ftm->SWOCTRL = 0; /* set prescale and mod registers to matching values for resolution and frequency */ ftm->SC = FTM_SC_PS(prescaler); ftm->MOD = res - 1; /* set PWM mode */ uint32_t mode_mask = 0; switch (mode) { case PWM_LEFT: mode_mask = (1 << FTM_CnSC_MSB_SHIFT) | (1 << FTM_CnSC_ELSB_SHIFT); break; case PWM_RIGHT: mode_mask = (1 << FTM_CnSC_MSB_SHIFT) | (1 << FTM_CnSC_ELSA_SHIFT); break; case PWM_CENTER: mode_mask = (1 << FTM_CnSC_MSB_SHIFT); ftm->SC |= (1 << FTM_SC_CPWMS_SHIFT); break; } for (int i = 0; i < channels; i++) { /* cppcheck thinks ftmchan may be NULL here, but the variable is * assigned in all non-returning branches of the switch at the top of * this function. */ /* cppcheck-suppress nullPointer ftmchan */ ftm->CONTROLS[ftmchan[i]].CnSC = mode_mask; } /* enable timer ergo the PWM generation */ pwm_start(dev); /* Return actual frequency */ return (pwm_clk / (1 << prescaler)) / res; } uint8_t pwm_channels(pwm_t dev) { switch (dev) { #if PWM_0_EN case PWM_0: return PWM_0_CHANNELS; #endif #if PWM_1_EN case PWM_1: return PWM_1_CHANNELS; #endif default: return 0; } } void pwm_set(pwm_t dev, uint8_t channel, uint16_t value) { FTM_Type *ftm; const uint8_t *ftmchan = NULL; switch (dev) { #if PWM_0_EN case PWM_0: if (channel > PWM_0_CHANNELS) { return; } ftm = PWM_0_DEV; ftmchan = &ftm0chan[0]; break; #endif #if PWM_1_EN case PWM_1: if (channel > PWM_1_CHANNELS) { return; } ftm = PWM_1_DEV; ftmchan = &ftm1chan[0]; break; #endif default: return; } /* clamp value to maximum possible value */ if (value > PWM_MAX_VALUE) { value = PWM_MAX_VALUE; } /* cppcheck thinks ftmchan may be NULL here, but the variable is * assigned in all non-returning branches of the switch at the top of * this function. */ /* cppcheck-suppress nullPointer */ ftm->CONTROLS[ftmchan[channel]].CnV = value; } void pwm_start(pwm_t dev) { switch (dev) { #if PWM_0_EN case PWM_0: PWM_0_DEV->SC |= FTM_SC_CLKS(1); break; #endif #if PWM_1_EN case PWM_1: PWM_1_DEV->SC |= FTM_SC_CLKS(1); break; #endif } } void pwm_stop(pwm_t dev) { switch (dev) { #if PWM_0_EN case PWM_0: PWM_0_DEV->SC &= ~FTM_SC_CLKS_MASK; break; #endif #if PWM_1_EN case PWM_1: PWM_1_DEV->SC &= ~FTM_SC_CLKS_MASK; break; #endif } } void pwm_poweron(pwm_t dev) { switch (dev) { #if PWM_0_EN case PWM_0: PWM_0_CLKEN(); break; #endif #if PWM_1_EN case PWM_1: PWM_1_CLKEN(); break; #endif } } void pwm_poweroff(pwm_t dev) { switch (dev) { #if PWM_0_EN case PWM_0: PWM_0_CLKDIS(); break; #endif #if PWM_1_EN case PWM_1: PWM_1_CLKDIS(); break; #endif } }