tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Freescale/TARGET_KLXX/pwmout_api.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include "mbed_assert.h"
  17 #include "pwmout_api.h"
  18
  19 #include "cmsis.h"
  20 #include "pinmap.h"
  21 #include "clk_freqs.h"
  22 #include "PeripheralPins.h"
  23
  24 static float pwm_clock;
  25
  26 void pwmout_init(pwmout_t* obj, PinName pin) {
  27     // determine the channel
  28     PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
  29     MBED_ASSERT(pwm != (PWMName)NC);
  30
  31     uint32_t clkdiv = 0;
  32     float clkval;
  33
  34 #if defined(TARGET_KL43Z)
  35     if (mcgirc_frequency()) {
  36         SIM->SOPT2 |= SIM_SOPT2_TPMSRC(3); // Clock source: MCGIRCLK
  37         clkval = mcgirc_frequency() / 1000000.0f;
  38     } else {
  39         SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1); // Clock source: IRC48M
  40         clkval = CPU_INT_IRC_CLK_HZ / 1000000.0f;
  41     }
  42 #else
  43     if (mcgpllfll_frequency()) {
  44         SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1); // Clock source: MCGFLLCLK or MCGPLLCLK
  45         clkval = mcgpllfll_frequency() / 1000000.0f;
  46     } else {
  47         SIM->SOPT2 |= SIM_SOPT2_TPMSRC(2); // Clock source: ExtOsc
  48         clkval = extosc_frequency() / 1000000.0f;
  49     }
  50 #endif
  51     while (clkval > 1) {
  52         clkdiv++;
  53         clkval /= 2.0;
  54         if (clkdiv == 7)
  55             break;
  56     }
  57
  58     pwm_clock = clkval;
  59     unsigned int port  = (unsigned int)pin >> PORT_SHIFT;
  60     unsigned int tpm_n = (pwm >> TPM_SHIFT);
  61     unsigned int ch_n  = (pwm & 0xFF);
  62
  63     SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
  64     SIM->SCGC6 |= 1 << (SIM_SCGC6_TPM0_SHIFT + tpm_n);
  65
  66     TPM_Type *tpm = (TPM_Type *)(TPM0_BASE + 0x1000 * tpm_n);
  67     tpm->SC = TPM_SC_CMOD(1) | TPM_SC_PS(clkdiv); // (clock)MHz / clkdiv ~= (0.75)MHz
  68     tpm->CONTROLS[ch_n].CnSC = (TPM_CnSC_MSB_MASK | TPM_CnSC_ELSB_MASK); /* No Interrupts; High True pulses on Edge Aligned PWM */
  69
  70     obj->CnV = &tpm->CONTROLS[ch_n].CnV;
  71     obj->MOD = &tpm->MOD;
  72     obj->CNT = &tpm->CNT;
  73
  74     // default to 20ms: standard for servos, and fine for e.g. brightness control
  75     pwmout_period_ms(obj, 20);
  76     pwmout_write    (obj, 0);
  77
  78     // Wire pinout
  79     pinmap_pinout(pin, PinMap_PWM);
  80 }
  81
  82 void pwmout_free(pwmout_t* obj) {}
  83
  84 void pwmout_write(pwmout_t* obj, float value) {
  85     if (value < 0.0) {
  86         value = 0.0;
  87     } else if (value > 1.0) {
  88         value = 1.0;
  89     }
  90
  91     *obj->CnV = (uint32_t)((float)(*obj->MOD + 1) * value);
  92     *obj->CNT = 0;
  93 }
  94
  95 float pwmout_read(pwmout_t* obj) {
  96     float v = (float)(*obj->CnV) / (float)(*obj->MOD + 1);
  97     return (v > 1.0) ? (1.0) : (v);
  98 }
  99
 100 void pwmout_period(pwmout_t* obj, float seconds) {
 101     pwmout_period_us(obj, seconds * 1000000.0f);
 102 }
 103
 104 void pwmout_period_ms(pwmout_t* obj, int ms) {
 105     pwmout_period_us(obj, ms * 1000);
 106 }
 107
 108 // Set the PWM period, keeping the duty cycle the same.
 109 void pwmout_period_us(pwmout_t* obj, int us) {
 110     float dc = pwmout_read(obj);
 111     *obj->MOD = (uint32_t)(pwm_clock * (float)us) - 1;
 112     pwmout_write(obj, dc);
 113 }
 114
 115 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
 116     pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
 117 }
 118
 119 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
 120     pwmout_pulsewidth_us(obj, ms * 1000);
 121 }
 122
 123 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
 124     *obj->CnV = (uint32_t)(pwm_clock * (float)us);
 125 }