Umar Naeem / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed-dev by Umar Naeem

targets/TARGET_NXP/TARGET_LPC11UXX/pwmout_api.c@149:156823d33999, 2016-10-28 (annotated)

Committer:
<>
Date:
Fri Oct 28 11:17:30 2016 +0100
Revision:
149:156823d33999
Parent:
targets/hal/TARGET_NXP/TARGET_LPC11UXX/pwmout_api.c@144:ef7eb2e8f9f7 
This updates the lib to the mbed lib v128



NOTE: This release includes a restructuring of the file and directory locations and thus some

include paths in your code may need updating accordingly.

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 #include "cmsis.h"
<> 144:ef7eb2e8f9f7 19 #include "pinmap.h"
<> 144:ef7eb2e8f9f7 20 #include "PeripheralPins.h" // For the Peripheral to Pin Definitions found in the individual Target's Platform
<> 144:ef7eb2e8f9f7 21
<> 144:ef7eb2e8f9f7 22 #define TCR_CNT_EN 0x00000001
<> 144:ef7eb2e8f9f7 23 #define TCR_RESET 0x00000002
<> 144:ef7eb2e8f9f7 24
<> 144:ef7eb2e8f9f7 25 typedef struct {
<> 144:ef7eb2e8f9f7 26 uint8_t timer;
<> 144:ef7eb2e8f9f7 27 uint8_t mr;
<> 144:ef7eb2e8f9f7 28 } timer_mr;
<> 144:ef7eb2e8f9f7 29
<> 144:ef7eb2e8f9f7 30 static timer_mr pwm_timer_map[11] = {
<> 144:ef7eb2e8f9f7 31 {0, 0}, {0, 1}, {0, 2},
<> 144:ef7eb2e8f9f7 32 {1, 0}, {1, 1},
<> 144:ef7eb2e8f9f7 33 {2, 0}, {2, 1}, {2, 2},
<> 144:ef7eb2e8f9f7 34 {3, 0}, {3, 1}, {3, 2},
<> 144:ef7eb2e8f9f7 35 };
<> 144:ef7eb2e8f9f7 36
<> 144:ef7eb2e8f9f7 37 static LPC_CTxxBx_Type *Timers[4] = {
<> 144:ef7eb2e8f9f7 38 LPC_CT16B0, LPC_CT16B1,
<> 144:ef7eb2e8f9f7 39 LPC_CT32B0, LPC_CT32B1
<> 144:ef7eb2e8f9f7 40 };
<> 144:ef7eb2e8f9f7 41
<> 144:ef7eb2e8f9f7 42 void pwmout_init(pwmout_t* obj, PinName pin) {
<> 144:ef7eb2e8f9f7 43 // determine the channel
<> 144:ef7eb2e8f9f7 44 PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
<> 144:ef7eb2e8f9f7 45 MBED_ASSERT(pwm != (PWMName)NC);
<> 144:ef7eb2e8f9f7 46
<> 144:ef7eb2e8f9f7 47 obj->pwm = pwm;
<> 144:ef7eb2e8f9f7 48
<> 144:ef7eb2e8f9f7 49 // Timer registers
<> 144:ef7eb2e8f9f7 50 timer_mr tid = pwm_timer_map[pwm];
<> 144:ef7eb2e8f9f7 51 LPC_CTxxBx_Type *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 52
<> 144:ef7eb2e8f9f7 53 // Disable timer
<> 144:ef7eb2e8f9f7 54 timer->TCR = 0;
<> 144:ef7eb2e8f9f7 55
<> 144:ef7eb2e8f9f7 56 // Power the correspondent timer
<> 144:ef7eb2e8f9f7 57 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << (tid.timer + 7);
<> 144:ef7eb2e8f9f7 58
<> 144:ef7eb2e8f9f7 59 /* Enable PWM function */
<> 144:ef7eb2e8f9f7 60 timer->PWMC = (1 << 3)|(1 << 2)|(1 << 1)|(1 << 0);
<> 144:ef7eb2e8f9f7 61
<> 144:ef7eb2e8f9f7 62 /* Reset Functionality on MR3 controlling the PWM period */
<> 144:ef7eb2e8f9f7 63 timer->MCR = 1 << 10;
<> 144:ef7eb2e8f9f7 64
<> 144:ef7eb2e8f9f7 65 // default to 20ms: standard for servos, and fine for e.g. brightness control
<> 144:ef7eb2e8f9f7 66 pwmout_period_ms(obj, 20);
<> 144:ef7eb2e8f9f7 67 pwmout_write (obj, 0);
<> 144:ef7eb2e8f9f7 68
<> 144:ef7eb2e8f9f7 69 // Wire pinout
<> 144:ef7eb2e8f9f7 70 pinmap_pinout(pin, PinMap_PWM);
<> 144:ef7eb2e8f9f7 71 }
<> 144:ef7eb2e8f9f7 72
<> 144:ef7eb2e8f9f7 73 void pwmout_free(pwmout_t* obj) {
<> 144:ef7eb2e8f9f7 74 // [TODO]
<> 144:ef7eb2e8f9f7 75 }
<> 144:ef7eb2e8f9f7 76
<> 144:ef7eb2e8f9f7 77 void pwmout_write(pwmout_t* obj, float value) {
<> 144:ef7eb2e8f9f7 78 if (value < 0.0f) {
<> 144:ef7eb2e8f9f7 79 value = 0.0;
<> 144:ef7eb2e8f9f7 80 } else if (value > 1.0f) {
<> 144:ef7eb2e8f9f7 81 value = 1.0;
<> 144:ef7eb2e8f9f7 82 }
<> 144:ef7eb2e8f9f7 83
<> 144:ef7eb2e8f9f7 84 timer_mr tid = pwm_timer_map[obj->pwm];
<> 144:ef7eb2e8f9f7 85 LPC_CTxxBx_Type *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 86 uint32_t t_off = timer->MR3 - (uint32_t)((float)(timer->MR3) * value);
<> 144:ef7eb2e8f9f7 87
<> 144:ef7eb2e8f9f7 88 timer->MR[tid.mr] = t_off;
<> 144:ef7eb2e8f9f7 89 }
<> 144:ef7eb2e8f9f7 90
<> 144:ef7eb2e8f9f7 91 float pwmout_read(pwmout_t* obj) {
<> 144:ef7eb2e8f9f7 92 timer_mr tid = pwm_timer_map[obj->pwm];
<> 144:ef7eb2e8f9f7 93 LPC_CTxxBx_Type *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 94
<> 144:ef7eb2e8f9f7 95 float v = (float)(timer->MR3 - timer->MR[tid.mr]) / (float)(timer->MR3);
<> 144:ef7eb2e8f9f7 96 return (v > 1.0f) ? (1.0f) : (v);
<> 144:ef7eb2e8f9f7 97 }
<> 144:ef7eb2e8f9f7 98
<> 144:ef7eb2e8f9f7 99 void pwmout_period(pwmout_t* obj, float seconds) {
<> 144:ef7eb2e8f9f7 100 pwmout_period_us(obj, seconds * 1000000.0f);
<> 144:ef7eb2e8f9f7 101 }
<> 144:ef7eb2e8f9f7 102
<> 144:ef7eb2e8f9f7 103 void pwmout_period_ms(pwmout_t* obj, int ms) {
<> 144:ef7eb2e8f9f7 104 pwmout_period_us(obj, ms * 1000);
<> 144:ef7eb2e8f9f7 105 }
<> 144:ef7eb2e8f9f7 106
<> 144:ef7eb2e8f9f7 107 // Set the PWM period, keeping the duty cycle the same.
<> 144:ef7eb2e8f9f7 108 void pwmout_period_us(pwmout_t* obj, int us) {
<> 144:ef7eb2e8f9f7 109 int i = 0;
<> 144:ef7eb2e8f9f7 110 uint32_t period_ticks = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000);
<> 144:ef7eb2e8f9f7 111
<> 144:ef7eb2e8f9f7 112 timer_mr tid = pwm_timer_map[obj->pwm];
<> 144:ef7eb2e8f9f7 113 LPC_CTxxBx_Type *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 114 uint32_t old_period_ticks = timer->MR3;
<> 144:ef7eb2e8f9f7 115
<> 144:ef7eb2e8f9f7 116 // for 16bit timer, set prescaler to avoid overflow
<> 144:ef7eb2e8f9f7 117 if (timer == LPC_CT16B0 || timer == LPC_CT16B1) {
<> 144:ef7eb2e8f9f7 118 uint16_t high_period_ticks = period_ticks >> 16;
<> 144:ef7eb2e8f9f7 119 timer->PR = high_period_ticks;
<> 144:ef7eb2e8f9f7 120 period_ticks /= (high_period_ticks + 1);
<> 144:ef7eb2e8f9f7 121 }
<> 144:ef7eb2e8f9f7 122
<> 144:ef7eb2e8f9f7 123 timer->TCR = TCR_RESET;
<> 144:ef7eb2e8f9f7 124 timer->MR3 = period_ticks;
<> 144:ef7eb2e8f9f7 125
<> 144:ef7eb2e8f9f7 126 // Scale the pulse width to preserve the duty ratio
<> 144:ef7eb2e8f9f7 127 if (old_period_ticks > 0) {
<> 144:ef7eb2e8f9f7 128 for (i=0; i<3; i++) {
<> 144:ef7eb2e8f9f7 129 uint32_t t_off = period_ticks - (uint32_t)(((uint64_t)timer->MR[i] * (uint64_t)period_ticks) / (uint64_t)old_period_ticks);
<> 144:ef7eb2e8f9f7 130 timer->MR[i] = t_off;
<> 144:ef7eb2e8f9f7 131 }
<> 144:ef7eb2e8f9f7 132 }
<> 144:ef7eb2e8f9f7 133 timer->TCR = TCR_CNT_EN;
<> 144:ef7eb2e8f9f7 134 }
<> 144:ef7eb2e8f9f7 135
<> 144:ef7eb2e8f9f7 136 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
<> 144:ef7eb2e8f9f7 137 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
<> 144:ef7eb2e8f9f7 138 }
<> 144:ef7eb2e8f9f7 139
<> 144:ef7eb2e8f9f7 140 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
<> 144:ef7eb2e8f9f7 141 pwmout_pulsewidth_us(obj, ms * 1000);
<> 144:ef7eb2e8f9f7 142 }
<> 144:ef7eb2e8f9f7 143
<> 144:ef7eb2e8f9f7 144 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
<> 144:ef7eb2e8f9f7 145 timer_mr tid = pwm_timer_map[obj->pwm];
<> 144:ef7eb2e8f9f7 146 LPC_CTxxBx_Type *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 147 uint32_t t_on = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000 / (timer->PR + 1));
<> 144:ef7eb2e8f9f7 148
<> 144:ef7eb2e8f9f7 149 timer->TCR = TCR_RESET;
<> 144:ef7eb2e8f9f7 150 if (t_on > timer->MR3) {
<> 144:ef7eb2e8f9f7 151 pwmout_period_us(obj, us);
<> 144:ef7eb2e8f9f7 152 t_on = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000 / (timer->PR + 1));
<> 144:ef7eb2e8f9f7 153 }
<> 144:ef7eb2e8f9f7 154 uint32_t t_off = timer->MR3 - t_on;
<> 144:ef7eb2e8f9f7 155 timer->MR[tid.mr] = t_off;
<> 144:ef7eb2e8f9f7 156 timer->TCR = TCR_CNT_EN;
<> 144:ef7eb2e8f9f7 157 }