mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

Dependents:   Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more

targets/hal/TARGET_Freescale/TARGET_K20XX/pwmout_api.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Child:
144:ef7eb2e8f9f7
Initial commit on mbed-dev



Replaces mbed-src (now inactive)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 0:9b334a45a8ff 1 /* mbed Microcontroller Library
bogdanm 0:9b334a45a8ff 2 * Copyright (c) 2006-2015 ARM Limited
bogdanm 0:9b334a45a8ff 3 *
bogdanm 0:9b334a45a8ff 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 0:9b334a45a8ff 5 * you may not use this file except in compliance with the License.
bogdanm 0:9b334a45a8ff 6 * You may obtain a copy of the License at
bogdanm 0:9b334a45a8ff 7 *
bogdanm 0:9b334a45a8ff 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 0:9b334a45a8ff 9 *
bogdanm 0:9b334a45a8ff 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 0:9b334a45a8ff 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 0:9b334a45a8ff 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 0:9b334a45a8ff 13 * See the License for the specific language governing permissions and
bogdanm 0:9b334a45a8ff 14 * limitations under the License.
bogdanm 0:9b334a45a8ff 15 */
bogdanm 0:9b334a45a8ff 16 #include "mbed_assert.h"
bogdanm 0:9b334a45a8ff 17 #include "pwmout_api.h"
bogdanm 0:9b334a45a8ff 18
bogdanm 0:9b334a45a8ff 19 #include "cmsis.h"
bogdanm 0:9b334a45a8ff 20 #include "pinmap.h"
bogdanm 0:9b334a45a8ff 21 #include "PeripheralPins.h"
bogdanm 0:9b334a45a8ff 22
bogdanm 0:9b334a45a8ff 23 static float pwm_clock = 0;
bogdanm 0:9b334a45a8ff 24
bogdanm 0:9b334a45a8ff 25 void pwmout_init(pwmout_t* obj, PinName pin) {
bogdanm 0:9b334a45a8ff 26 // determine the channel
bogdanm 0:9b334a45a8ff 27 PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
bogdanm 0:9b334a45a8ff 28 MBED_ASSERT(pwm != (PWMName)NC);
bogdanm 0:9b334a45a8ff 29
bogdanm 0:9b334a45a8ff 30 uint32_t clkdiv = 0;
bogdanm 0:9b334a45a8ff 31 float clkval = SystemCoreClock / 1000000.0f;
bogdanm 0:9b334a45a8ff 32
bogdanm 0:9b334a45a8ff 33 while (clkval > 1) {
bogdanm 0:9b334a45a8ff 34 clkdiv++;
bogdanm 0:9b334a45a8ff 35 clkval /= 2.0;
bogdanm 0:9b334a45a8ff 36 if (clkdiv == 7)
bogdanm 0:9b334a45a8ff 37 break;
bogdanm 0:9b334a45a8ff 38 }
bogdanm 0:9b334a45a8ff 39
bogdanm 0:9b334a45a8ff 40 pwm_clock = clkval;
bogdanm 0:9b334a45a8ff 41 unsigned int ftm_n = (pwm >> TPM_SHIFT);
bogdanm 0:9b334a45a8ff 42 unsigned int ch_n = (pwm & 0xFF);
bogdanm 0:9b334a45a8ff 43
bogdanm 0:9b334a45a8ff 44 SIM->SCGC6 |= 1 << (SIM_SCGC6_FTM0_SHIFT + ftm_n);
bogdanm 0:9b334a45a8ff 45
bogdanm 0:9b334a45a8ff 46 FTM_Type *ftm = (FTM_Type *)(FTM0_BASE + 0x1000 * ftm_n);
bogdanm 0:9b334a45a8ff 47 ftm->CONF |= FTM_CONF_BDMMODE(3);
bogdanm 0:9b334a45a8ff 48 ftm->SC = FTM_SC_CLKS(1) | FTM_SC_PS(clkdiv); // (clock)MHz / clkdiv ~= (0.75)MHz
bogdanm 0:9b334a45a8ff 49 ftm->CONTROLS[ch_n].CnSC = (FTM_CnSC_MSB_MASK | FTM_CnSC_ELSB_MASK); /* No Interrupts; High True pulses on Edge Aligned PWM */
bogdanm 0:9b334a45a8ff 50 ftm->MODE = FTM_MODE_FTMEN_MASK;
bogdanm 0:9b334a45a8ff 51 ftm->SYNC = FTM_SYNC_CNTMIN_MASK;
bogdanm 0:9b334a45a8ff 52 ftm->SYNCONF = FTM_SYNCONF_SYNCMODE_MASK | FTM_SYNCONF_SWSOC_MASK | FTM_SYNCONF_SWWRBUF_MASK;
bogdanm 0:9b334a45a8ff 53
bogdanm 0:9b334a45a8ff 54 //Without SYNCEN set CnV does not seem to update
bogdanm 0:9b334a45a8ff 55 ftm->COMBINE = FTM_COMBINE_SYNCEN0_MASK | FTM_COMBINE_SYNCEN1_MASK | FTM_COMBINE_SYNCEN2_MASK | FTM_COMBINE_SYNCEN3_MASK;
bogdanm 0:9b334a45a8ff 56
bogdanm 0:9b334a45a8ff 57 obj->CnV = &ftm->CONTROLS[ch_n].CnV;
bogdanm 0:9b334a45a8ff 58 obj->MOD = &ftm->MOD;
bogdanm 0:9b334a45a8ff 59 obj->SYNC = &ftm->SYNC;
bogdanm 0:9b334a45a8ff 60
bogdanm 0:9b334a45a8ff 61 // default to 20ms: standard for servos, and fine for e.g. brightness control
bogdanm 0:9b334a45a8ff 62 pwmout_period_ms(obj, 20);
bogdanm 0:9b334a45a8ff 63 pwmout_write(obj, 0.0);
bogdanm 0:9b334a45a8ff 64
bogdanm 0:9b334a45a8ff 65 // Wire pinout
bogdanm 0:9b334a45a8ff 66 pinmap_pinout(pin, PinMap_PWM);
bogdanm 0:9b334a45a8ff 67 }
bogdanm 0:9b334a45a8ff 68
bogdanm 0:9b334a45a8ff 69 void pwmout_free(pwmout_t* obj) {}
bogdanm 0:9b334a45a8ff 70
bogdanm 0:9b334a45a8ff 71 void pwmout_write(pwmout_t* obj, float value) {
bogdanm 0:9b334a45a8ff 72 if (value < 0.0) {
bogdanm 0:9b334a45a8ff 73 value = 0.0;
bogdanm 0:9b334a45a8ff 74 } else if (value > 1.0) {
bogdanm 0:9b334a45a8ff 75 value = 1.0;
bogdanm 0:9b334a45a8ff 76 }
bogdanm 0:9b334a45a8ff 77
bogdanm 0:9b334a45a8ff 78 while(*obj->SYNC & FTM_SYNC_SWSYNC_MASK);
bogdanm 0:9b334a45a8ff 79 *obj->CnV = (uint32_t)((float)(*obj->MOD + 1) * value);
bogdanm 0:9b334a45a8ff 80 *obj->SYNC |= FTM_SYNC_SWSYNC_MASK;
bogdanm 0:9b334a45a8ff 81 }
bogdanm 0:9b334a45a8ff 82
bogdanm 0:9b334a45a8ff 83 float pwmout_read(pwmout_t* obj) {
bogdanm 0:9b334a45a8ff 84 while(*obj->SYNC & FTM_SYNC_SWSYNC_MASK);
bogdanm 0:9b334a45a8ff 85 float v = (float)(*obj->CnV) / (float)(*obj->MOD + 1);
bogdanm 0:9b334a45a8ff 86 return (v > 1.0) ? (1.0) : (v);
bogdanm 0:9b334a45a8ff 87 }
bogdanm 0:9b334a45a8ff 88
bogdanm 0:9b334a45a8ff 89 void pwmout_period(pwmout_t* obj, float seconds) {
bogdanm 0:9b334a45a8ff 90 pwmout_period_us(obj, seconds * 1000000.0f);
bogdanm 0:9b334a45a8ff 91 }
bogdanm 0:9b334a45a8ff 92
bogdanm 0:9b334a45a8ff 93 void pwmout_period_ms(pwmout_t* obj, int ms) {
bogdanm 0:9b334a45a8ff 94 pwmout_period_us(obj, ms * 1000);
bogdanm 0:9b334a45a8ff 95 }
bogdanm 0:9b334a45a8ff 96
bogdanm 0:9b334a45a8ff 97 // Set the PWM period, keeping the duty cycle the same.
bogdanm 0:9b334a45a8ff 98 void pwmout_period_us(pwmout_t* obj, int us) {
bogdanm 0:9b334a45a8ff 99 float dc = pwmout_read(obj);
bogdanm 0:9b334a45a8ff 100 *obj->MOD = (uint32_t)(pwm_clock * (float)us) - 1;
bogdanm 0:9b334a45a8ff 101 *obj->SYNC |= FTM_SYNC_SWSYNC_MASK;
bogdanm 0:9b334a45a8ff 102 pwmout_write(obj, dc);
bogdanm 0:9b334a45a8ff 103 }
bogdanm 0:9b334a45a8ff 104
bogdanm 0:9b334a45a8ff 105 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
bogdanm 0:9b334a45a8ff 106 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
bogdanm 0:9b334a45a8ff 107 }
bogdanm 0:9b334a45a8ff 108
bogdanm 0:9b334a45a8ff 109 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
bogdanm 0:9b334a45a8ff 110 pwmout_pulsewidth_us(obj, ms * 1000);
bogdanm 0:9b334a45a8ff 111 }
bogdanm 0:9b334a45a8ff 112
bogdanm 0:9b334a45a8ff 113 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
bogdanm 0:9b334a45a8ff 114 *obj->CnV = (uint32_t)(pwm_clock * (float)us);
bogdanm 0:9b334a45a8ff 115 *obj->SYNC |= FTM_SYNC_SWSYNC_MASK;
bogdanm 0:9b334a45a8ff 116 }