Johannes Stratmann / mbed-dev

added prescaler for 16 bit pwm in LPC1347 target

Fork of mbed-dev by mbed official

targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_K66F/pwmout_api.c@144:ef7eb2e8f9f7, 2016-09-02 (annotated)

Committer:
<>
Date:
Fri Sep 02 15:07:44 2016 +0100
Revision:
144:ef7eb2e8f9f7
This updates the lib to the mbed lib v125

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /* mbed Microcontroller Library
<> 144:ef7eb2e8f9f7 2 * Copyright (c) 2006-2013 ARM Limited
<> 144:ef7eb2e8f9f7 3 *
<> 144:ef7eb2e8f9f7 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 144:ef7eb2e8f9f7 5 * you may not use this file except in compliance with the License.
<> 144:ef7eb2e8f9f7 6 * You may obtain a copy of the License at
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Unless required by applicable law or agreed to in writing, software
<> 144:ef7eb2e8f9f7 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 144:ef7eb2e8f9f7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 144:ef7eb2e8f9f7 13 * See the License for the specific language governing permissions and
<> 144:ef7eb2e8f9f7 14 * limitations under the License.
<> 144:ef7eb2e8f9f7 15 */
<> 144:ef7eb2e8f9f7 16 #include "mbed_assert.h"
<> 144:ef7eb2e8f9f7 17 #include "pwmout_api.h"
<> 144:ef7eb2e8f9f7 18
<> 144:ef7eb2e8f9f7 19 #if DEVICE_PWMOUT
<> 144:ef7eb2e8f9f7 20
<> 144:ef7eb2e8f9f7 21 #include "cmsis.h"
<> 144:ef7eb2e8f9f7 22 #include "pinmap.h"
<> 144:ef7eb2e8f9f7 23 #include "fsl_ftm.h"
<> 144:ef7eb2e8f9f7 24 #include "PeripheralPins.h"
<> 144:ef7eb2e8f9f7 25
<> 144:ef7eb2e8f9f7 26 static float pwm_clock_mhz;
<> 144:ef7eb2e8f9f7 27 /* Array of FTM peripheral base address. */
<> 144:ef7eb2e8f9f7 28 static FTM_Type *const ftm_addrs[] = FTM_BASE_PTRS;
<> 144:ef7eb2e8f9f7 29
<> 144:ef7eb2e8f9f7 30 void pwmout_init(pwmout_t* obj, PinName pin) {
<> 144:ef7eb2e8f9f7 31 PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
<> 144:ef7eb2e8f9f7 32 MBED_ASSERT(pwm != (PWMName)NC);
<> 144:ef7eb2e8f9f7 33
<> 144:ef7eb2e8f9f7 34 obj->pwm_name = pwm;
<> 144:ef7eb2e8f9f7 35
<> 144:ef7eb2e8f9f7 36 uint32_t pwm_base_clock;
<> 144:ef7eb2e8f9f7 37 pwm_base_clock = CLOCK_GetFreq(kCLOCK_BusClk);
<> 144:ef7eb2e8f9f7 38 float clkval = (float)pwm_base_clock / 1000000.0f;
<> 144:ef7eb2e8f9f7 39 uint32_t clkdiv = 0;
<> 144:ef7eb2e8f9f7 40 while (clkval > 1) {
<> 144:ef7eb2e8f9f7 41 clkdiv++;
<> 144:ef7eb2e8f9f7 42 clkval /= 2.0f;
<> 144:ef7eb2e8f9f7 43 if (clkdiv == 7) {
<> 144:ef7eb2e8f9f7 44 break;
<> 144:ef7eb2e8f9f7 45 }
<> 144:ef7eb2e8f9f7 46 }
<> 144:ef7eb2e8f9f7 47
<> 144:ef7eb2e8f9f7 48 pwm_clock_mhz = clkval;
<> 144:ef7eb2e8f9f7 49 uint32_t channel = pwm & 0xF;
<> 144:ef7eb2e8f9f7 50 uint32_t instance = pwm >> TPM_SHIFT;
<> 144:ef7eb2e8f9f7 51 ftm_config_t ftmInfo;
<> 144:ef7eb2e8f9f7 52
<> 144:ef7eb2e8f9f7 53 FTM_GetDefaultConfig(&ftmInfo);
<> 144:ef7eb2e8f9f7 54 ftmInfo.prescale = (ftm_clock_prescale_t)clkdiv;
<> 144:ef7eb2e8f9f7 55 /* Initialize FTM module */
<> 144:ef7eb2e8f9f7 56 FTM_Init(ftm_addrs[instance], &ftmInfo);
<> 144:ef7eb2e8f9f7 57
<> 144:ef7eb2e8f9f7 58 ftm_addrs[instance]->CONF |= FTM_CONF_NUMTOF(3);
<> 144:ef7eb2e8f9f7 59
<> 144:ef7eb2e8f9f7 60 ftm_chnl_pwm_signal_param_t config = {
<> 144:ef7eb2e8f9f7 61 .chnlNumber = (ftm_chnl_t)channel,
<> 144:ef7eb2e8f9f7 62 .level = kFTM_HighTrue,
<> 144:ef7eb2e8f9f7 63 .dutyCyclePercent = 0,
<> 144:ef7eb2e8f9f7 64 .firstEdgeDelayPercent = 0
<> 144:ef7eb2e8f9f7 65 };
<> 144:ef7eb2e8f9f7 66 // default to 20ms: standard for servos, and fine for e.g. brightness control
<> 144:ef7eb2e8f9f7 67 FTM_SetupPwm(ftm_addrs[instance], &config, 1, kFTM_EdgeAlignedPwm, 50, pwm_base_clock);
<> 144:ef7eb2e8f9f7 68
<> 144:ef7eb2e8f9f7 69 FTM_StartTimer(ftm_addrs[instance], kFTM_SystemClock);
<> 144:ef7eb2e8f9f7 70
<> 144:ef7eb2e8f9f7 71 // Wire pinout
<> 144:ef7eb2e8f9f7 72 pinmap_pinout(pin, PinMap_PWM);
<> 144:ef7eb2e8f9f7 73 }
<> 144:ef7eb2e8f9f7 74
<> 144:ef7eb2e8f9f7 75 void pwmout_free(pwmout_t* obj) {
<> 144:ef7eb2e8f9f7 76 FTM_Deinit(ftm_addrs[obj->pwm_name >> TPM_SHIFT]);
<> 144:ef7eb2e8f9f7 77 }
<> 144:ef7eb2e8f9f7 78
<> 144:ef7eb2e8f9f7 79 void pwmout_write(pwmout_t* obj, float value) {
<> 144:ef7eb2e8f9f7 80 if (value < 0.0f) {
<> 144:ef7eb2e8f9f7 81 value = 0.0f;
<> 144:ef7eb2e8f9f7 82 } else if (value > 1.0f) {
<> 144:ef7eb2e8f9f7 83 value = 1.0f;
<> 144:ef7eb2e8f9f7 84 }
<> 144:ef7eb2e8f9f7 85
<> 144:ef7eb2e8f9f7 86 FTM_Type *base = ftm_addrs[obj->pwm_name >> TPM_SHIFT];
<> 144:ef7eb2e8f9f7 87 uint16_t mod = base->MOD & FTM_MOD_MOD_MASK;
<> 144:ef7eb2e8f9f7 88 uint32_t new_count = (uint32_t)((float)(mod) * value);
<> 144:ef7eb2e8f9f7 89 // Update of CnV register
<> 144:ef7eb2e8f9f7 90 base->CONTROLS[obj->pwm_name & 0xF].CnV = new_count;
<> 144:ef7eb2e8f9f7 91 base->CNT = 0;
<> 144:ef7eb2e8f9f7 92 /* Software trigger to update registers */
<> 144:ef7eb2e8f9f7 93 FTM_SetSoftwareTrigger(base, true);
<> 144:ef7eb2e8f9f7 94 }
<> 144:ef7eb2e8f9f7 95
<> 144:ef7eb2e8f9f7 96 float pwmout_read(pwmout_t* obj) {
<> 144:ef7eb2e8f9f7 97 FTM_Type *base = ftm_addrs[obj->pwm_name >> TPM_SHIFT];
<> 144:ef7eb2e8f9f7 98 uint16_t count = (base->CONTROLS[obj->pwm_name & 0xF].CnV) & FTM_CnV_VAL_MASK;
<> 144:ef7eb2e8f9f7 99 uint16_t mod = base->MOD & FTM_MOD_MOD_MASK;
<> 144:ef7eb2e8f9f7 100
<> 144:ef7eb2e8f9f7 101 if (mod == 0)
<> 144:ef7eb2e8f9f7 102 return 0.0;
<> 144:ef7eb2e8f9f7 103 float v = (float)(count) / (float)(mod);
<> 144:ef7eb2e8f9f7 104 return (v > 1.0f) ? (1.0f) : (v);
<> 144:ef7eb2e8f9f7 105 }
<> 144:ef7eb2e8f9f7 106
<> 144:ef7eb2e8f9f7 107 void pwmout_period(pwmout_t* obj, float seconds) {
<> 144:ef7eb2e8f9f7 108 pwmout_period_us(obj, seconds * 1000000.0f);
<> 144:ef7eb2e8f9f7 109 }
<> 144:ef7eb2e8f9f7 110
<> 144:ef7eb2e8f9f7 111 void pwmout_period_ms(pwmout_t* obj, int ms) {
<> 144:ef7eb2e8f9f7 112 pwmout_period_us(obj, ms * 1000);
<> 144:ef7eb2e8f9f7 113 }
<> 144:ef7eb2e8f9f7 114
<> 144:ef7eb2e8f9f7 115 // Set the PWM period, keeping the duty cycle the same.
<> 144:ef7eb2e8f9f7 116 void pwmout_period_us(pwmout_t* obj, int us) {
<> 144:ef7eb2e8f9f7 117 FTM_Type *base = ftm_addrs[obj->pwm_name >> TPM_SHIFT];
<> 144:ef7eb2e8f9f7 118 float dc = pwmout_read(obj);
<> 144:ef7eb2e8f9f7 119
<> 144:ef7eb2e8f9f7 120 // Stop FTM clock to ensure instant update of MOD register
<> 144:ef7eb2e8f9f7 121 base->MOD = FTM_MOD_MOD((pwm_clock_mhz * (float)us) - 1);
<> 144:ef7eb2e8f9f7 122 pwmout_write(obj, dc);
<> 144:ef7eb2e8f9f7 123 }
<> 144:ef7eb2e8f9f7 124
<> 144:ef7eb2e8f9f7 125 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
<> 144:ef7eb2e8f9f7 126 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
<> 144:ef7eb2e8f9f7 127 }
<> 144:ef7eb2e8f9f7 128
<> 144:ef7eb2e8f9f7 129 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
<> 144:ef7eb2e8f9f7 130 pwmout_pulsewidth_us(obj, ms * 1000);
<> 144:ef7eb2e8f9f7 131 }
<> 144:ef7eb2e8f9f7 132
<> 144:ef7eb2e8f9f7 133 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
<> 144:ef7eb2e8f9f7 134 FTM_Type *base = ftm_addrs[obj->pwm_name >> TPM_SHIFT];
<> 144:ef7eb2e8f9f7 135 uint32_t value = (uint32_t)(pwm_clock_mhz * (float)us);
<> 144:ef7eb2e8f9f7 136
<> 144:ef7eb2e8f9f7 137 // Update of CnV register
<> 144:ef7eb2e8f9f7 138 base->CONTROLS[obj->pwm_name & 0xF].CnV = value;
<> 144:ef7eb2e8f9f7 139 /* Software trigger to update registers */
<> 144:ef7eb2e8f9f7 140 FTM_SetSoftwareTrigger(base, true);
<> 144:ef7eb2e8f9f7 141 }
<> 144:ef7eb2e8f9f7 142
<> 144:ef7eb2e8f9f7 143 #endif