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targets/TARGET_Atmel/TARGET_SAM_CortexM4/pwmout_api.c
- Committer:
- amithy
- Date:
- 2017-11-09
- Revision:
- 178:c26431f84b0d
- Parent:
- 149:156823d33999
File content as of revision 178:c26431f84b0d:
/* mbed Microcontroller Library * Copyright (c) 2006-2015 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. */ #include "mbed_assert.h" #include "pwmout_api.h" #include "cmsis.h" #include "tc.h" #include "sysclk.h" #include "PeripheralPins.h" extern uint8_t g_sys_init; /** Use TC Peripheral 0 **/ #define TC TC0 static const uint32_t tc_prescalar[] = { TC_CMR_TCCLKS_TIMER_CLOCK1, // MCK/2 TC_CMR_TCCLKS_TIMER_CLOCK2, // MCK/8 TC_CMR_TCCLKS_TIMER_CLOCK3, // MCK/32 TC_CMR_TCCLKS_TIMER_CLOCK4, // MCK/128 }; static const uint32_t tc_prescalar_divider[] = { 2, // MCK/2 8, // MCK/8 32, // MCK/32 128 // MCK/128 }; uint32_t getpwmchannelid (uint32_t channel) { switch (channel) { case 0 : return ID_TC0; case 1 : return ID_TC1; case 2 : return ID_TC2; default : MBED_ASSERT(false); break; } } uint32_t getprescalarindex (uint16_t frequency) { float time_period_ms; time_period_ms = (1.0 / (float)frequency) * 1000.0; if (time_period_ms <= 1.0) { return 0; } else if ((time_period_ms > 1.0) && (time_period_ms <= 4.0)) { return 1; } else if ((time_period_ms > 4.0) && (time_period_ms <= 16.0)) { return 2; } else { return 3; } } static void setregisterabc (pwmout_t* obj) { uint32_t ra, rb, rc; /* Sanity check arguments */ MBED_ASSERT(obj); /* Configure waveform frequency and duty cycle. */ rc = (sysclk_get_peripheral_bus_hz(TC) / tc_prescalar_divider[obj->prescalarindex] )/ obj->waveconfig.us_frequency; tc_write_rc(TC, obj->channel, rc); switch (obj->ioline) { case 0 : ra = (100 - obj->waveconfig.us_dutycycle) * rc / 100; if(ra <= 0) ra = 1; /*non zero value only*/ tc_write_ra(TC, obj->channel, ra); break; case 1 : rb = (100 - obj->waveconfig.us_dutycycle) * rc / 100; if(rb <= 0) rb = 1; /*non zero value only*/ tc_write_rb(TC, obj->channel, rb); break; default : MBED_ASSERT(false); break; } } void pwmout_inithw(pwmout_t* obj) { uint32_t mode = 0; /* Configure the PMC to enable the TC module. */ sysclk_enable_peripheral_clock(getpwmchannelid(obj->channel)); #if SAMG55 /* Enable PCK output */ pmc_disable_pck(PMC_PCK_3); pmc_switch_pck_to_mck(PMC_PCK_3, PMC_PCK_PRES_CLK_1); pmc_enable_pck(PMC_PCK_3); #endif switch (obj->ioline) { case 0 : mode = TC_CMR_ACPA_SET | TC_CMR_ACPC_CLEAR; /* RA Compare Effect: set */ /* RC Compare Effect: clear */ break; case 1 : mode = TC_CMR_BCPB_SET | TC_CMR_BCPC_CLEAR | TC_CMR_ABETRG; /* RB Compare Effect: set */ /* RC Compare Effect: clear */ /*Change external event selection from TIOB*/ break; default : MBED_ASSERT(false); break; } /* Disable TC TC_CHANNEL_WAVEFORM. */ tc_stop(TC, obj->channel); /* Init TC to waveform mode. */ tc_init(TC, obj->channel, /* Waveform Clock Selection */ obj->waveconfig.ul_intclock | TC_CMR_WAVE /* Waveform mode is enabled */ | TC_CMR_CPCTRG /* UP mode with automatic trigger on RC Compare */ | mode ); } /** Initialize PWM Module * * @param[in][out] obj The PWM object to initialize * @return void */ void pwmout_init(pwmout_t* obj, PinName pin) { /* Sanity check arguments */ MBED_ASSERT(obj); uint32_t ioline = NC; uint32_t channel = NC; if (g_sys_init == 0) { sysclk_init(); system_board_init(); g_sys_init = 1; } if(pin != NC) { pin_function(pin, pinmap_find_function(pin, PinMap_PWM)); ioport_disable_pin(pin); } obj->pin = pin; ioline = pinmap_find_function(pin, PinMap_PWM_IO_Line); /*To find out which IO Line is associated with the pin and initialise accordingly*/ /*pinmap_find_function reused to find out iolin used*/ MBED_ASSERT(ioline != NC); obj->ioline = ioline; channel = pinmap_find_peripheral(pin, PinMap_PWM_IO_Line); /* PinMap_PWM_IO_Line contains channel number and ioline to be used*/ /*pinmap_find_peripheral function reused to find out channel number*/ MBED_ASSERT(channel != NC); obj->channel = channel; obj->waveconfig.us_frequency = 500; obj->waveconfig.us_dutycycle = 50; obj->prescalarindex = getprescalarindex(obj->waveconfig.us_frequency); obj->waveconfig.ul_intclock = tc_prescalar[obj->prescalarindex]; pwmout_inithw(obj); /*Set the registers a,b,c*/ setregisterabc(obj); /* Enable TC TC_CHANNEL_WAVEFORM. */ tc_start(TC, channel); } /** Free the PWM Module * * @param[in] obj The PWM object to free * @return void */ void pwmout_free(pwmout_t* obj) { /* Sanity check arguments */ MBED_ASSERT(obj); tc_stop(TC, obj->channel); } /** Set the duty cycle of PWM Waveform * * @param[in] obj The PWM object * @param[in] value New duty cycle to be set * @return void */ void pwmout_write(pwmout_t* obj, float value) { /* Sanity check arguments */ MBED_ASSERT(obj); if (value < 0.0f) { value = 0; } else if (value > 1.0f) { value = 1; } obj->waveconfig.us_dutycycle = (uint16_t)(value * 100); tc_stop(TC, obj->channel); /*Set the registers a,b,c*/ setregisterabc(obj); /* Enable TC TC_CHANNEL_WAVEFORM. */ tc_start(TC, obj->channel); } /** Get the duty cycle of PWM Waveform * * @param[in] obj The PWM object * @return Current duty cycle */ float pwmout_read(pwmout_t* obj) { /* Sanity check arguments */ MBED_ASSERT(obj); return (obj->waveconfig.us_dutycycle / 100.0); } /** Set the period of PWM Waveform * * @param[in] obj The PWM object * @param[in] seconds New period in seconds * @return void */ void pwmout_period(pwmout_t* obj, float seconds) { pwmout_period_us(obj, seconds * 1000000.0f); } /** Set the period of PWM Waveform * * @param[in] obj The PWM object * @param[in] value New period in milliseconds * @return void */ void pwmout_period_ms(pwmout_t* obj, int ms) { pwmout_period_us(obj, ms * 1000); } /** Set the period of PWM Waveform * * @param[in] obj The PWM object * @param[in] us New period in microseconds * @return void */ void pwmout_period_us(pwmout_t* obj, int us) { /* Sanity check arguments */ MBED_ASSERT(obj); float freq = ( 1.0 / us ) * 1000000.0; obj->waveconfig.us_frequency = (uint16_t) freq; obj->prescalarindex = getprescalarindex(obj->waveconfig.us_frequency); obj->waveconfig.ul_intclock = tc_prescalar[obj->prescalarindex]; pwmout_inithw(obj); /*Set the registers a,b,c*/ setregisterabc(obj); /* Enable TC TC_CHANNEL_WAVEFORM. */ tc_start(TC, obj->channel); } /** Set the pulse width of PWM Waveform * * @param[in] obj The PWM object * @param[in] seconds New pulse width in seconds * @return void */ void pwmout_pulsewidth(pwmout_t* obj, float seconds) { pwmout_pulsewidth_us(obj, seconds * 1000000.0f); } /** Set the pulse width of PWM Waveform * * @param[in] obj The PWM object * @param[in] ms New pulse width in milliseconds * @return void */ void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) { pwmout_pulsewidth_us(obj, ms * 1000); } /** Set the pulse width of PWM Waveform * * @param[in] obj The PWM object * @param[in] us New pulse width in microseconds * @return void */ void pwmout_pulsewidth_us(pwmout_t* obj, int us) { /* Sanity check arguments */ MBED_ASSERT(obj); float new_duty = (us / 1000000.0) * (float)obj->waveconfig.us_frequency; pwmout_write(obj, new_duty); }