mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

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

targets/TARGET_NXP/TARGET_LPC11XX_11CXX/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_LPC11XX_11CXX/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
<> 144:ef7eb2e8f9f7 21 #define TCR_CNT_EN 0x00000001
<> 144:ef7eb2e8f9f7 22 #define TCR_RESET 0x00000002
<> 144:ef7eb2e8f9f7 23
<> 144:ef7eb2e8f9f7 24 /* To have a PWM where we can change both the period and the duty cycle,
<> 144:ef7eb2e8f9f7 25 * we need an entire timer. With the following conventions:
<> 144:ef7eb2e8f9f7 26 * * MR3 is used for the PWM period
<> 144:ef7eb2e8f9f7 27 * * MR0, MR1, MR2 are used for the duty cycle
<> 144:ef7eb2e8f9f7 28 */
<> 144:ef7eb2e8f9f7 29 static const PinMap PinMap_PWM[] = {
<> 144:ef7eb2e8f9f7 30 /* CT16B0 */
<> 144:ef7eb2e8f9f7 31 {P0_8 , PWM_1, 0x02}, /* MR0 */
<> 144:ef7eb2e8f9f7 32 {P0_9 , PWM_2, 0x02}, /* MR1 */
<> 144:ef7eb2e8f9f7 33
<> 144:ef7eb2e8f9f7 34 /* CT16B1 */
<> 144:ef7eb2e8f9f7 35 {P1_9 , PWM_3, 0x01}, /* MR0 */
<> 144:ef7eb2e8f9f7 36 {P1_10, PWM_4, 0x02}, /* MR1 */
<> 144:ef7eb2e8f9f7 37
<> 144:ef7eb2e8f9f7 38 /* CT32B0 */
<> 144:ef7eb2e8f9f7 39 {P0_1 , PWM_5, 0x02}, /* MR2 */
<> 144:ef7eb2e8f9f7 40
<> 144:ef7eb2e8f9f7 41 {NC , NC ,0x00}
<> 144:ef7eb2e8f9f7 42 };
<> 144:ef7eb2e8f9f7 43
<> 144:ef7eb2e8f9f7 44 typedef struct {
<> 144:ef7eb2e8f9f7 45 uint8_t timer;
<> 144:ef7eb2e8f9f7 46 uint8_t mr;
<> 144:ef7eb2e8f9f7 47 } timer_mr;
<> 144:ef7eb2e8f9f7 48
<> 144:ef7eb2e8f9f7 49 static timer_mr pwm_timer_map[5] = {
<> 144:ef7eb2e8f9f7 50 {0, 0}, /* CT16B0, MR0 */
<> 144:ef7eb2e8f9f7 51 {0, 1}, /* CT16B0, MR1 */
<> 144:ef7eb2e8f9f7 52
<> 144:ef7eb2e8f9f7 53 {1, 0}, /* CT16B1, MR0 */
<> 144:ef7eb2e8f9f7 54 {1, 1}, /* CT16B1, MR1 */
<> 144:ef7eb2e8f9f7 55
<> 144:ef7eb2e8f9f7 56 {2, 2}, /* CT32B0, MR2 */
<> 144:ef7eb2e8f9f7 57 };
<> 144:ef7eb2e8f9f7 58
<> 144:ef7eb2e8f9f7 59 static LPC_TMR_TypeDef *Timers[3] = {
<> 144:ef7eb2e8f9f7 60 LPC_TMR16B0, LPC_TMR16B1,
<> 144:ef7eb2e8f9f7 61 LPC_TMR32B0
<> 144:ef7eb2e8f9f7 62 };
<> 144:ef7eb2e8f9f7 63
<> 144:ef7eb2e8f9f7 64 void pwmout_init(pwmout_t* obj, PinName pin) {
<> 144:ef7eb2e8f9f7 65 // determine the channel
<> 144:ef7eb2e8f9f7 66 PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
<> 144:ef7eb2e8f9f7 67 MBED_ASSERT(pwm != (PWMName)NC);
<> 144:ef7eb2e8f9f7 68
<> 144:ef7eb2e8f9f7 69 obj->pwm = pwm;
<> 144:ef7eb2e8f9f7 70
<> 144:ef7eb2e8f9f7 71 // Timer registers
<> 144:ef7eb2e8f9f7 72 timer_mr tid = pwm_timer_map[pwm];
<> 144:ef7eb2e8f9f7 73 LPC_TMR_TypeDef *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 74
<> 144:ef7eb2e8f9f7 75 // Disable timer
<> 144:ef7eb2e8f9f7 76 timer->TCR = 0;
<> 144:ef7eb2e8f9f7 77
<> 144:ef7eb2e8f9f7 78 // Power the correspondent timer
<> 144:ef7eb2e8f9f7 79 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << (tid.timer + 7);
<> 144:ef7eb2e8f9f7 80
<> 144:ef7eb2e8f9f7 81 /* Enable PWM function */
<> 144:ef7eb2e8f9f7 82 timer->PWMC = (1 << 3)|(1 << 2)|(1 << 1)|(1 << 0);
<> 144:ef7eb2e8f9f7 83
<> 144:ef7eb2e8f9f7 84 /* Reset Functionality on MR3 controlling the PWM period */
<> 144:ef7eb2e8f9f7 85 timer->MCR = 1 << 10;
<> 144:ef7eb2e8f9f7 86
<> 144:ef7eb2e8f9f7 87 if (timer == LPC_TMR16B0 || timer == LPC_TMR16B1) {
<> 144:ef7eb2e8f9f7 88 /* Set 16-bit timer prescaler to avoid timer expire for default 20ms */
<> 144:ef7eb2e8f9f7 89 /* This can be also modified by user application, but the prescaler value */
<> 144:ef7eb2e8f9f7 90 /* might be trade-off to timer accuracy */
<> 144:ef7eb2e8f9f7 91 timer->PR = 30;
<> 144:ef7eb2e8f9f7 92 }
<> 144:ef7eb2e8f9f7 93
<> 144:ef7eb2e8f9f7 94 // default to 20ms: standard for servos, and fine for e.g. brightness control
<> 144:ef7eb2e8f9f7 95 pwmout_period_ms(obj, 20);
<> 144:ef7eb2e8f9f7 96 pwmout_write (obj, 0);
<> 144:ef7eb2e8f9f7 97
<> 144:ef7eb2e8f9f7 98 // Wire pinout
<> 144:ef7eb2e8f9f7 99 pinmap_pinout(pin, PinMap_PWM);
<> 144:ef7eb2e8f9f7 100 }
<> 144:ef7eb2e8f9f7 101
<> 144:ef7eb2e8f9f7 102 void pwmout_free(pwmout_t* obj) {
<> 144:ef7eb2e8f9f7 103 // [TODO]
<> 144:ef7eb2e8f9f7 104 }
<> 144:ef7eb2e8f9f7 105
<> 144:ef7eb2e8f9f7 106 void pwmout_write(pwmout_t* obj, float value) {
<> 144:ef7eb2e8f9f7 107 if (value < 0.0f) {
<> 144:ef7eb2e8f9f7 108 value = 0.0;
<> 144:ef7eb2e8f9f7 109 } else if (value > 1.0f) {
<> 144:ef7eb2e8f9f7 110 value = 1.0;
<> 144:ef7eb2e8f9f7 111 }
<> 144:ef7eb2e8f9f7 112
<> 144:ef7eb2e8f9f7 113 timer_mr tid = pwm_timer_map[obj->pwm];
<> 144:ef7eb2e8f9f7 114 LPC_TMR_TypeDef *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 115 uint32_t t_off = timer->MR3 - (uint32_t)((float)(timer->MR3) * value);
<> 144:ef7eb2e8f9f7 116 // to avoid spike pulse when duty is 0%
<> 144:ef7eb2e8f9f7 117 if (value == 0) {
<> 144:ef7eb2e8f9f7 118 t_off++;
<> 144:ef7eb2e8f9f7 119 }
<> 144:ef7eb2e8f9f7 120
<> 144:ef7eb2e8f9f7 121 timer->TCR = TCR_RESET;
<> 144:ef7eb2e8f9f7 122 timer->MR[tid.mr] = t_off;
<> 144:ef7eb2e8f9f7 123 timer->TCR = TCR_CNT_EN;
<> 144:ef7eb2e8f9f7 124 }
<> 144:ef7eb2e8f9f7 125
<> 144:ef7eb2e8f9f7 126 float pwmout_read(pwmout_t* obj) {
<> 144:ef7eb2e8f9f7 127 timer_mr tid = pwm_timer_map[obj->pwm];
<> 144:ef7eb2e8f9f7 128 LPC_TMR_TypeDef *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 129
<> 144:ef7eb2e8f9f7 130 float v = (float)(timer->MR3 - timer->MR[tid.mr]) / (float)(timer->MR3);
<> 144:ef7eb2e8f9f7 131 if (timer->MR[tid.mr] > timer->MR3) {
<> 144:ef7eb2e8f9f7 132 v = 0.0f;
<> 144:ef7eb2e8f9f7 133 }
<> 144:ef7eb2e8f9f7 134 return (v > 1.0f) ? (1.0f) : (v);
<> 144:ef7eb2e8f9f7 135 }
<> 144:ef7eb2e8f9f7 136
<> 144:ef7eb2e8f9f7 137 void pwmout_period(pwmout_t* obj, float seconds) {
<> 144:ef7eb2e8f9f7 138 pwmout_period_us(obj, seconds * 1000000.0f);
<> 144:ef7eb2e8f9f7 139 }
<> 144:ef7eb2e8f9f7 140
<> 144:ef7eb2e8f9f7 141 void pwmout_period_ms(pwmout_t* obj, int ms) {
<> 144:ef7eb2e8f9f7 142 pwmout_period_us(obj, ms * 1000);
<> 144:ef7eb2e8f9f7 143 }
<> 144:ef7eb2e8f9f7 144
<> 144:ef7eb2e8f9f7 145 // Set the PWM period, keeping the duty cycle the same.
<> 144:ef7eb2e8f9f7 146 void pwmout_period_us(pwmout_t* obj, int us) {
<> 144:ef7eb2e8f9f7 147 int i = 0;
<> 144:ef7eb2e8f9f7 148 uint32_t period_ticks;
<> 144:ef7eb2e8f9f7 149
<> 144:ef7eb2e8f9f7 150 timer_mr tid = pwm_timer_map[obj->pwm];
<> 144:ef7eb2e8f9f7 151 LPC_TMR_TypeDef *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 152 uint32_t old_period_ticks = timer->MR3;
<> 144:ef7eb2e8f9f7 153 period_ticks = (SystemCoreClock / 1000000 * us) / (timer->PR + 1);
<> 144:ef7eb2e8f9f7 154
<> 144:ef7eb2e8f9f7 155 timer->TCR = TCR_RESET;
<> 144:ef7eb2e8f9f7 156 timer->MR3 = period_ticks;
<> 144:ef7eb2e8f9f7 157
<> 144:ef7eb2e8f9f7 158 // Scale the pulse width to preserve the duty ratio
<> 144:ef7eb2e8f9f7 159 if (old_period_ticks > 0) {
<> 144:ef7eb2e8f9f7 160 for (i=0; i<3; i++) {
<> 144:ef7eb2e8f9f7 161 uint32_t t_off = period_ticks - (uint32_t)(((uint64_t)timer->MR[i] * (uint64_t)period_ticks) / (uint64_t)old_period_ticks);
<> 144:ef7eb2e8f9f7 162 timer->MR[i] = t_off;
<> 144:ef7eb2e8f9f7 163 }
<> 144:ef7eb2e8f9f7 164 }
<> 144:ef7eb2e8f9f7 165 timer->TCR = TCR_CNT_EN;
<> 144:ef7eb2e8f9f7 166 }
<> 144:ef7eb2e8f9f7 167
<> 144:ef7eb2e8f9f7 168 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
<> 144:ef7eb2e8f9f7 169 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
<> 144:ef7eb2e8f9f7 170 }
<> 144:ef7eb2e8f9f7 171
<> 144:ef7eb2e8f9f7 172 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
<> 144:ef7eb2e8f9f7 173 pwmout_pulsewidth_us(obj, ms * 1000);
<> 144:ef7eb2e8f9f7 174 }
<> 144:ef7eb2e8f9f7 175
<> 144:ef7eb2e8f9f7 176 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
<> 144:ef7eb2e8f9f7 177 timer_mr tid = pwm_timer_map[obj->pwm];
<> 144:ef7eb2e8f9f7 178 LPC_TMR_TypeDef *timer = Timers[tid.timer];
<> 144:ef7eb2e8f9f7 179 uint32_t t_on = (uint32_t)((((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000) / (timer->PR + 1));
<> 144:ef7eb2e8f9f7 180
<> 144:ef7eb2e8f9f7 181 timer->TCR = TCR_RESET;
<> 144:ef7eb2e8f9f7 182 if (t_on > timer->MR3) {
<> 144:ef7eb2e8f9f7 183 pwmout_period_us(obj, us);
<> 144:ef7eb2e8f9f7 184 }
<> 144:ef7eb2e8f9f7 185 uint32_t t_off = timer->MR3 - t_on;
<> 144:ef7eb2e8f9f7 186 timer->MR[tid.mr] = t_off;
<> 144:ef7eb2e8f9f7 187 timer->TCR = TCR_CNT_EN;
<> 144:ef7eb2e8f9f7 188 }