mirror of https://github.com/ARMmbed/mbed-os.git
126 lines
3.7 KiB
C
126 lines
3.7 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2006-2013 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "mbed_assert.h"
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#include "pwmout_api.h"
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#include "cmsis.h"
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#include "pinmap.h"
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#include "clk_freqs.h"
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#include "PeripheralPins.h"
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static float pwm_clock;
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void pwmout_init(pwmout_t* obj, PinName pin) {
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// determine the channel
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PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
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MBED_ASSERT(pwm != (PWMName)NC);
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uint32_t clkdiv = 0;
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float clkval;
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#if defined(TARGET_KL43Z)
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if (mcgirc_frequency()) {
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SIM->SOPT2 |= SIM_SOPT2_TPMSRC(3); // Clock source: MCGIRCLK
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clkval = mcgirc_frequency() / 1000000.0f;
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} else {
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SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1); // Clock source: IRC48M
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clkval = CPU_INT_IRC_CLK_HZ / 1000000.0f;
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}
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#else
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if (mcgpllfll_frequency()) {
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SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1); // Clock source: MCGFLLCLK or MCGPLLCLK
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clkval = mcgpllfll_frequency() / 1000000.0f;
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} else {
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SIM->SOPT2 |= SIM_SOPT2_TPMSRC(2); // Clock source: ExtOsc
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clkval = extosc_frequency() / 1000000.0f;
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}
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#endif
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while (clkval > 1) {
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clkdiv++;
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clkval /= 2.0;
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if (clkdiv == 7)
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break;
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}
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pwm_clock = clkval;
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unsigned int port = (unsigned int)pin >> PORT_SHIFT;
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unsigned int tpm_n = (pwm >> TPM_SHIFT);
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unsigned int ch_n = (pwm & 0xFF);
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SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
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SIM->SCGC6 |= 1 << (SIM_SCGC6_TPM0_SHIFT + tpm_n);
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TPM_Type *tpm = (TPM_Type *)(TPM0_BASE + 0x1000 * tpm_n);
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tpm->SC = TPM_SC_CMOD(1) | TPM_SC_PS(clkdiv); // (clock)MHz / clkdiv ~= (0.75)MHz
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tpm->CONTROLS[ch_n].CnSC = (TPM_CnSC_MSB_MASK | TPM_CnSC_ELSB_MASK); /* No Interrupts; High True pulses on Edge Aligned PWM */
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obj->CnV = &tpm->CONTROLS[ch_n].CnV;
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obj->MOD = &tpm->MOD;
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obj->CNT = &tpm->CNT;
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// default to 20ms: standard for servos, and fine for e.g. brightness control
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pwmout_period_ms(obj, 20);
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pwmout_write (obj, 0);
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// Wire pinout
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pinmap_pinout(pin, PinMap_PWM);
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}
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void pwmout_free(pwmout_t* obj) {}
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void pwmout_write(pwmout_t* obj, float value) {
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if (value < 0.0) {
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value = 0.0;
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} else if (value > 1.0) {
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value = 1.0;
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}
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*obj->CnV = (uint32_t)((float)(*obj->MOD + 1) * value);
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*obj->CNT = 0;
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}
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float pwmout_read(pwmout_t* obj) {
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float v = (float)(*obj->CnV) / (float)(*obj->MOD + 1);
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return (v > 1.0) ? (1.0) : (v);
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}
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void pwmout_period(pwmout_t* obj, float seconds) {
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pwmout_period_us(obj, seconds * 1000000.0f);
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}
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void pwmout_period_ms(pwmout_t* obj, int ms) {
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pwmout_period_us(obj, ms * 1000);
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}
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// Set the PWM period, keeping the duty cycle the same.
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void pwmout_period_us(pwmout_t* obj, int us) {
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float dc = pwmout_read(obj);
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*obj->MOD = (uint32_t)(pwm_clock * (float)us) - 1;
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pwmout_write(obj, dc);
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}
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void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
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pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
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}
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void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
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pwmout_pulsewidth_us(obj, ms * 1000);
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}
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void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
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*obj->CnV = (uint32_t)(pwm_clock * (float)us);
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}
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