added prescaler for 16 bit pwm in LPC1347 target
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Diff: targets/hal/TARGET_Freescale/TARGET_K20XX/pwmout_api.c
- Revision:
- 144:ef7eb2e8f9f7
- Parent:
- 0:9b334a45a8ff
--- a/targets/hal/TARGET_Freescale/TARGET_K20XX/pwmout_api.c Tue Aug 02 14:07:36 2016 +0000 +++ b/targets/hal/TARGET_Freescale/TARGET_K20XX/pwmout_api.c Fri Sep 02 15:07:44 2016 +0100 @@ -1,116 +1,116 @@ -/* 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 "pinmap.h" -#include "PeripheralPins.h" - -static float pwm_clock = 0; - -void pwmout_init(pwmout_t* obj, PinName pin) { - // determine the channel - PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM); - MBED_ASSERT(pwm != (PWMName)NC); - - uint32_t clkdiv = 0; - float clkval = SystemCoreClock / 1000000.0f; - - while (clkval > 1) { - clkdiv++; - clkval /= 2.0; - if (clkdiv == 7) - break; - } - - pwm_clock = clkval; - unsigned int ftm_n = (pwm >> TPM_SHIFT); - unsigned int ch_n = (pwm & 0xFF); - - SIM->SCGC6 |= 1 << (SIM_SCGC6_FTM0_SHIFT + ftm_n); - - FTM_Type *ftm = (FTM_Type *)(FTM0_BASE + 0x1000 * ftm_n); - ftm->CONF |= FTM_CONF_BDMMODE(3); - ftm->SC = FTM_SC_CLKS(1) | FTM_SC_PS(clkdiv); // (clock)MHz / clkdiv ~= (0.75)MHz - ftm->CONTROLS[ch_n].CnSC = (FTM_CnSC_MSB_MASK | FTM_CnSC_ELSB_MASK); /* No Interrupts; High True pulses on Edge Aligned PWM */ - ftm->MODE = FTM_MODE_FTMEN_MASK; - ftm->SYNC = FTM_SYNC_CNTMIN_MASK; - ftm->SYNCONF = FTM_SYNCONF_SYNCMODE_MASK | FTM_SYNCONF_SWSOC_MASK | FTM_SYNCONF_SWWRBUF_MASK; - - //Without SYNCEN set CnV does not seem to update - ftm->COMBINE = FTM_COMBINE_SYNCEN0_MASK | FTM_COMBINE_SYNCEN1_MASK | FTM_COMBINE_SYNCEN2_MASK | FTM_COMBINE_SYNCEN3_MASK; - - obj->CnV = &ftm->CONTROLS[ch_n].CnV; - obj->MOD = &ftm->MOD; - obj->SYNC = &ftm->SYNC; - - // default to 20ms: standard for servos, and fine for e.g. brightness control - pwmout_period_ms(obj, 20); - pwmout_write(obj, 0.0); - - // Wire pinout - pinmap_pinout(pin, PinMap_PWM); -} - -void pwmout_free(pwmout_t* obj) {} - -void pwmout_write(pwmout_t* obj, float value) { - if (value < 0.0) { - value = 0.0; - } else if (value > 1.0) { - value = 1.0; - } - - while(*obj->SYNC & FTM_SYNC_SWSYNC_MASK); - *obj->CnV = (uint32_t)((float)(*obj->MOD + 1) * value); - *obj->SYNC |= FTM_SYNC_SWSYNC_MASK; -} - -float pwmout_read(pwmout_t* obj) { - while(*obj->SYNC & FTM_SYNC_SWSYNC_MASK); - float v = (float)(*obj->CnV) / (float)(*obj->MOD + 1); - return (v > 1.0) ? (1.0) : (v); -} - -void pwmout_period(pwmout_t* obj, float seconds) { - pwmout_period_us(obj, seconds * 1000000.0f); -} - -void pwmout_period_ms(pwmout_t* obj, int ms) { - pwmout_period_us(obj, ms * 1000); -} - -// Set the PWM period, keeping the duty cycle the same. -void pwmout_period_us(pwmout_t* obj, int us) { - float dc = pwmout_read(obj); - *obj->MOD = (uint32_t)(pwm_clock * (float)us) - 1; - *obj->SYNC |= FTM_SYNC_SWSYNC_MASK; - pwmout_write(obj, dc); -} - -void pwmout_pulsewidth(pwmout_t* obj, float seconds) { - pwmout_pulsewidth_us(obj, seconds * 1000000.0f); -} - -void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) { - pwmout_pulsewidth_us(obj, ms * 1000); -} - -void pwmout_pulsewidth_us(pwmout_t* obj, int us) { - *obj->CnV = (uint32_t)(pwm_clock * (float)us); - *obj->SYNC |= FTM_SYNC_SWSYNC_MASK; -} +/* 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 "pinmap.h" +#include "PeripheralPins.h" + +static float pwm_clock = 0; + +void pwmout_init(pwmout_t* obj, PinName pin) { + // determine the channel + PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM); + MBED_ASSERT(pwm != (PWMName)NC); + + uint32_t clkdiv = 0; + float clkval = SystemCoreClock / 1000000.0f; + + while (clkval > 1) { + clkdiv++; + clkval /= 2.0; + if (clkdiv == 7) + break; + } + + pwm_clock = clkval; + unsigned int ftm_n = (pwm >> TPM_SHIFT); + unsigned int ch_n = (pwm & 0xFF); + + SIM->SCGC6 |= 1 << (SIM_SCGC6_FTM0_SHIFT + ftm_n); + + FTM_Type *ftm = (FTM_Type *)(FTM0_BASE + 0x1000 * ftm_n); + ftm->CONF |= FTM_CONF_BDMMODE(3); + ftm->SC = FTM_SC_CLKS(1) | FTM_SC_PS(clkdiv); // (clock)MHz / clkdiv ~= (0.75)MHz + ftm->CONTROLS[ch_n].CnSC = (FTM_CnSC_MSB_MASK | FTM_CnSC_ELSB_MASK); /* No Interrupts; High True pulses on Edge Aligned PWM */ + ftm->MODE = FTM_MODE_FTMEN_MASK; + ftm->SYNC = FTM_SYNC_CNTMIN_MASK; + ftm->SYNCONF = FTM_SYNCONF_SYNCMODE_MASK | FTM_SYNCONF_SWSOC_MASK | FTM_SYNCONF_SWWRBUF_MASK; + + //Without SYNCEN set CnV does not seem to update + ftm->COMBINE = FTM_COMBINE_SYNCEN0_MASK | FTM_COMBINE_SYNCEN1_MASK | FTM_COMBINE_SYNCEN2_MASK | FTM_COMBINE_SYNCEN3_MASK; + + obj->CnV = &ftm->CONTROLS[ch_n].CnV; + obj->MOD = &ftm->MOD; + obj->SYNC = &ftm->SYNC; + + // default to 20ms: standard for servos, and fine for e.g. brightness control + pwmout_period_ms(obj, 20); + pwmout_write(obj, 0.0); + + // Wire pinout + pinmap_pinout(pin, PinMap_PWM); +} + +void pwmout_free(pwmout_t* obj) {} + +void pwmout_write(pwmout_t* obj, float value) { + if (value < 0.0) { + value = 0.0; + } else if (value > 1.0) { + value = 1.0; + } + + while(*obj->SYNC & FTM_SYNC_SWSYNC_MASK); + *obj->CnV = (uint32_t)((float)(*obj->MOD + 1) * value); + *obj->SYNC |= FTM_SYNC_SWSYNC_MASK; +} + +float pwmout_read(pwmout_t* obj) { + while(*obj->SYNC & FTM_SYNC_SWSYNC_MASK); + float v = (float)(*obj->CnV) / (float)(*obj->MOD + 1); + return (v > 1.0) ? (1.0) : (v); +} + +void pwmout_period(pwmout_t* obj, float seconds) { + pwmout_period_us(obj, seconds * 1000000.0f); +} + +void pwmout_period_ms(pwmout_t* obj, int ms) { + pwmout_period_us(obj, ms * 1000); +} + +// Set the PWM period, keeping the duty cycle the same. +void pwmout_period_us(pwmout_t* obj, int us) { + float dc = pwmout_read(obj); + *obj->MOD = (uint32_t)(pwm_clock * (float)us) - 1; + *obj->SYNC |= FTM_SYNC_SWSYNC_MASK; + pwmout_write(obj, dc); +} + +void pwmout_pulsewidth(pwmout_t* obj, float seconds) { + pwmout_pulsewidth_us(obj, seconds * 1000000.0f); +} + +void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) { + pwmout_pulsewidth_us(obj, ms * 1000); +} + +void pwmout_pulsewidth_us(pwmout_t* obj, int us) { + *obj->CnV = (uint32_t)(pwm_clock * (float)us); + *obj->SYNC |= FTM_SYNC_SWSYNC_MASK; +}