EL4121 Embedded System / mbed-os

mbed-os

Dependents:   cobaLCDJoyMotor_Thread odometry_omni_3roda_v3 odometry_omni_3roda_v1 odometry_omni_3roda_v2 ... more

targets/TARGET_NXP/TARGET_LPC11U6X/pwmout_api.c@0:b74591d5ab33, 2017-12-11 (annotated)

Committer:
be_bryan
Date:
Mon Dec 11 17:54:04 2017 +0000
Revision:
0:b74591d5ab33
motor ++

Who changed what in which revision?

UserRevisionLine numberNew contents of line
be_bryan 0:b74591d5ab33 1 /* mbed Microcontroller Library
be_bryan 0:b74591d5ab33 2 * Copyright (c) 2006-2013 ARM Limited
be_bryan 0:b74591d5ab33 3 *
be_bryan 0:b74591d5ab33 4 * Licensed under the Apache License, Version 2.0 (the "License");
be_bryan 0:b74591d5ab33 5 * you may not use this file except in compliance with the License.
be_bryan 0:b74591d5ab33 6 * You may obtain a copy of the License at
be_bryan 0:b74591d5ab33 7 *
be_bryan 0:b74591d5ab33 8 * http://www.apache.org/licenses/LICENSE-2.0
be_bryan 0:b74591d5ab33 9 *
be_bryan 0:b74591d5ab33 10 * Unless required by applicable law or agreed to in writing, software
be_bryan 0:b74591d5ab33 11 * distributed under the License is distributed on an "AS IS" BASIS,
be_bryan 0:b74591d5ab33 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
be_bryan 0:b74591d5ab33 13 * See the License for the specific language governing permissions and
be_bryan 0:b74591d5ab33 14 * limitations under the License.
be_bryan 0:b74591d5ab33 15 */
be_bryan 0:b74591d5ab33 16
be_bryan 0:b74591d5ab33 17 #include "pwmout_api.h"
be_bryan 0:b74591d5ab33 18 #include "cmsis.h"
be_bryan 0:b74591d5ab33 19 #include "pinmap.h"
be_bryan 0:b74591d5ab33 20 #include "mbed_error.h"
be_bryan 0:b74591d5ab33 21
be_bryan 0:b74591d5ab33 22 #if DEVICE_PWMOUT
be_bryan 0:b74591d5ab33 23
be_bryan 0:b74591d5ab33 24 #define SCT_CHANNELS 2
be_bryan 0:b74591d5ab33 25
be_bryan 0:b74591d5ab33 26 static const PinMap PinMap_PWM[] = {
be_bryan 0:b74591d5ab33 27 {P1_19, SCT0_0, 2},
be_bryan 0:b74591d5ab33 28 {P2_2 , SCT0_1, 3},
be_bryan 0:b74591d5ab33 29 {P2_7 , SCT0_2, 2},
be_bryan 0:b74591d5ab33 30 {P1_13, SCT0_3, 2},
be_bryan 0:b74591d5ab33 31 {P2_16, SCT1_0, 1},
be_bryan 0:b74591d5ab33 32 {P2_17, SCT1_1, 1},
be_bryan 0:b74591d5ab33 33 {P2_18, SCT1_2, 1},
be_bryan 0:b74591d5ab33 34 {P2_19, SCT1_3, 1},
be_bryan 0:b74591d5ab33 35 {NC , NC ,0}
be_bryan 0:b74591d5ab33 36 };
be_bryan 0:b74591d5ab33 37
be_bryan 0:b74591d5ab33 38
be_bryan 0:b74591d5ab33 39 static LPC_SCT0_Type *SCTs[SCT_CHANNELS] = {
be_bryan 0:b74591d5ab33 40 (LPC_SCT0_Type*)LPC_SCT0,
be_bryan 0:b74591d5ab33 41 (LPC_SCT0_Type*)LPC_SCT1,
be_bryan 0:b74591d5ab33 42
be_bryan 0:b74591d5ab33 43 };
be_bryan 0:b74591d5ab33 44
be_bryan 0:b74591d5ab33 45 // bit flags for used SCTs
be_bryan 0:b74591d5ab33 46 static unsigned char sct_used = 0;
be_bryan 0:b74591d5ab33 47
be_bryan 0:b74591d5ab33 48 static int get_available_sct(void) {
be_bryan 0:b74591d5ab33 49 int i;
be_bryan 0:b74591d5ab33 50 for (i=0; i<SCT_CHANNELS; i++) {
be_bryan 0:b74591d5ab33 51 if ((sct_used & (1 << i)) == 0)
be_bryan 0:b74591d5ab33 52 return i;
be_bryan 0:b74591d5ab33 53 }
be_bryan 0:b74591d5ab33 54 return -1;
be_bryan 0:b74591d5ab33 55 }
be_bryan 0:b74591d5ab33 56
be_bryan 0:b74591d5ab33 57 void pwmout_init(pwmout_t* obj, PinName pin) {
be_bryan 0:b74591d5ab33 58 // determine the SPI to use
be_bryan 0:b74591d5ab33 59 PWMName pwm_mapped = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
be_bryan 0:b74591d5ab33 60 if (pwm_mapped == (PWMName)NC) {
be_bryan 0:b74591d5ab33 61 error("PwmOut pin mapping failed");
be_bryan 0:b74591d5ab33 62 }
be_bryan 0:b74591d5ab33 63 int sct_n = get_available_sct();
be_bryan 0:b74591d5ab33 64 if (sct_n == -1) {
be_bryan 0:b74591d5ab33 65 error("No available SCT");
be_bryan 0:b74591d5ab33 66 }
be_bryan 0:b74591d5ab33 67
be_bryan 0:b74591d5ab33 68 sct_used |= (1 << sct_n);
be_bryan 0:b74591d5ab33 69 obj->pwm = SCTs[sct_n];
be_bryan 0:b74591d5ab33 70 obj->pwm_ch = sct_n;
be_bryan 0:b74591d5ab33 71
be_bryan 0:b74591d5ab33 72 // Enable the SCT clock
be_bryan 0:b74591d5ab33 73 LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 31);
be_bryan 0:b74591d5ab33 74
be_bryan 0:b74591d5ab33 75 // Clear peripheral reset the SCT:
be_bryan 0:b74591d5ab33 76 LPC_SYSCON->PRESETCTRL |= (1 << (obj->pwm_ch + 9));
be_bryan 0:b74591d5ab33 77 pinmap_pinout(pin, PinMap_PWM);
be_bryan 0:b74591d5ab33 78 LPC_SCT0_Type* pwm = obj->pwm;
be_bryan 0:b74591d5ab33 79
be_bryan 0:b74591d5ab33 80 // Unified 32-bit counter, autolimit
be_bryan 0:b74591d5ab33 81 pwm->CONFIG |= ((0x3 << 17) | 0x01);
be_bryan 0:b74591d5ab33 82
be_bryan 0:b74591d5ab33 83 // halt and clear the counter
be_bryan 0:b74591d5ab33 84 pwm->CTRL |= (1 << 2) | (1 << 3);
be_bryan 0:b74591d5ab33 85
be_bryan 0:b74591d5ab33 86 switch(pwm_mapped) {
be_bryan 0:b74591d5ab33 87 case SCT0_0:
be_bryan 0:b74591d5ab33 88 case SCT1_0:
be_bryan 0:b74591d5ab33 89 pwm->OUT0_SET = (1 << 0); // event 0
be_bryan 0:b74591d5ab33 90 pwm->OUT0_CLR = (1 << 1); // event 1
be_bryan 0:b74591d5ab33 91 break;
be_bryan 0:b74591d5ab33 92 case SCT0_1:
be_bryan 0:b74591d5ab33 93 case SCT1_1:
be_bryan 0:b74591d5ab33 94 pwm->OUT1_SET = (1 << 0); // event 0
be_bryan 0:b74591d5ab33 95 pwm->OUT1_CLR = (1 << 1); // event 1
be_bryan 0:b74591d5ab33 96 break;
be_bryan 0:b74591d5ab33 97 case SCT0_2:
be_bryan 0:b74591d5ab33 98 case SCT1_2:
be_bryan 0:b74591d5ab33 99 pwm->OUT2_SET = (1 << 0); // event 0
be_bryan 0:b74591d5ab33 100 pwm->OUT2_CLR = (1 << 1); // event 1
be_bryan 0:b74591d5ab33 101 break;
be_bryan 0:b74591d5ab33 102 case SCT0_3:
be_bryan 0:b74591d5ab33 103 case SCT1_3:
be_bryan 0:b74591d5ab33 104 pwm->OUT3_SET = (1 << 0); // event 0
be_bryan 0:b74591d5ab33 105 pwm->OUT3_CLR = (1 << 1); // event 1
be_bryan 0:b74591d5ab33 106 break;
be_bryan 0:b74591d5ab33 107 default:
be_bryan 0:b74591d5ab33 108 break;
be_bryan 0:b74591d5ab33 109 }
be_bryan 0:b74591d5ab33 110 // Event 0 : MATCH and MATCHSEL=0
be_bryan 0:b74591d5ab33 111 pwm->EV0_CTRL = (1 << 12);
be_bryan 0:b74591d5ab33 112 pwm->EV0_STATE = 0xFFFFFFFF;
be_bryan 0:b74591d5ab33 113 // Event 1 : MATCH and MATCHSEL=1
be_bryan 0:b74591d5ab33 114 pwm->EV1_CTRL = (1 << 12) | (1 << 0);
be_bryan 0:b74591d5ab33 115 pwm->EV1_STATE = 0xFFFFFFFF;
be_bryan 0:b74591d5ab33 116
be_bryan 0:b74591d5ab33 117 // default to 20ms: standard for servos, and fine for e.g. brightness control
be_bryan 0:b74591d5ab33 118 pwmout_period_ms(obj, 20);
be_bryan 0:b74591d5ab33 119 pwmout_write (obj, 0);
be_bryan 0:b74591d5ab33 120 }
be_bryan 0:b74591d5ab33 121
be_bryan 0:b74591d5ab33 122 void pwmout_free(pwmout_t* obj) {
be_bryan 0:b74591d5ab33 123 sct_used &= ~(1 << obj->pwm_ch);
be_bryan 0:b74591d5ab33 124 if (sct_used == 0) {
be_bryan 0:b74591d5ab33 125 // Disable the SCT clock
be_bryan 0:b74591d5ab33 126 LPC_SYSCON->SYSAHBCLKCTRL &= ~(1UL << 31);
be_bryan 0:b74591d5ab33 127 }
be_bryan 0:b74591d5ab33 128 }
be_bryan 0:b74591d5ab33 129
be_bryan 0:b74591d5ab33 130 void pwmout_write(pwmout_t* obj, float value) {
be_bryan 0:b74591d5ab33 131 LPC_SCT0_Type* pwm = obj->pwm;
be_bryan 0:b74591d5ab33 132 if (value < 0.0f) {
be_bryan 0:b74591d5ab33 133 value = 0.0;
be_bryan 0:b74591d5ab33 134 } else if (value > 1.0f) {
be_bryan 0:b74591d5ab33 135 value = 1.0;
be_bryan 0:b74591d5ab33 136 }
be_bryan 0:b74591d5ab33 137 uint32_t t_on = (uint32_t)((float)(pwm->MATCHREL0 + 1) * value);
be_bryan 0:b74591d5ab33 138 if (t_on > 0) {
be_bryan 0:b74591d5ab33 139 pwm->MATCHREL1 = t_on - 1;
be_bryan 0:b74591d5ab33 140
be_bryan 0:b74591d5ab33 141 // Un-halt the timer and ensure the new pulse-width takes immediate effect if necessary
be_bryan 0:b74591d5ab33 142 if (pwm->CTRL & (1 << 2)) {
be_bryan 0:b74591d5ab33 143 pwm->MATCH1 = pwm->MATCHREL1;
be_bryan 0:b74591d5ab33 144 pwm->CTRL &= ~(1 << 2);
be_bryan 0:b74591d5ab33 145 }
be_bryan 0:b74591d5ab33 146 } else {
be_bryan 0:b74591d5ab33 147 // Halt the timer and force the output low
be_bryan 0:b74591d5ab33 148 pwm->CTRL |= (1 << 2) | (1 << 3);
be_bryan 0:b74591d5ab33 149 pwm->OUTPUT = 0x00000000;
be_bryan 0:b74591d5ab33 150 }
be_bryan 0:b74591d5ab33 151 }
be_bryan 0:b74591d5ab33 152
be_bryan 0:b74591d5ab33 153 float pwmout_read(pwmout_t* obj) {
be_bryan 0:b74591d5ab33 154 LPC_SCT0_Type* pwm = obj->pwm;
be_bryan 0:b74591d5ab33 155 uint32_t t_off = pwm->MATCHREL0 + 1;
be_bryan 0:b74591d5ab33 156 uint32_t t_on = (!(pwm->CTRL & (1 << 2))) ? pwm->MATCHREL1 + 1 : 0;
be_bryan 0:b74591d5ab33 157 float v = (float)t_on/(float)t_off;
be_bryan 0:b74591d5ab33 158 return (v > 1.0f) ? (1.0f) : (v);
be_bryan 0:b74591d5ab33 159 }
be_bryan 0:b74591d5ab33 160
be_bryan 0:b74591d5ab33 161 void pwmout_period(pwmout_t* obj, float seconds) {
be_bryan 0:b74591d5ab33 162 pwmout_period_us(obj, seconds * 1000000.0f);
be_bryan 0:b74591d5ab33 163 }
be_bryan 0:b74591d5ab33 164
be_bryan 0:b74591d5ab33 165 void pwmout_period_ms(pwmout_t* obj, int ms) {
be_bryan 0:b74591d5ab33 166 pwmout_period_us(obj, ms * 1000);
be_bryan 0:b74591d5ab33 167 }
be_bryan 0:b74591d5ab33 168
be_bryan 0:b74591d5ab33 169 // Set the PWM period, keeping the duty cycle the same.
be_bryan 0:b74591d5ab33 170 void pwmout_period_us(pwmout_t* obj, int us) {
be_bryan 0:b74591d5ab33 171 LPC_SCT0_Type* pwm = obj->pwm;
be_bryan 0:b74591d5ab33 172 uint32_t t_off = pwm->MATCHREL0 + 1;
be_bryan 0:b74591d5ab33 173 uint32_t t_on = (!(pwm->CTRL & (1 << 2))) ? pwm->MATCHREL1 + 1 : 0;
be_bryan 0:b74591d5ab33 174 float v = (float)t_on/(float)t_off;
be_bryan 0:b74591d5ab33 175 uint32_t period_ticks = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000);
be_bryan 0:b74591d5ab33 176 uint32_t pulsewidth_ticks = period_ticks * v;
be_bryan 0:b74591d5ab33 177 pwm->MATCHREL0 = period_ticks - 1;
be_bryan 0:b74591d5ab33 178 if (pulsewidth_ticks > 0) {
be_bryan 0:b74591d5ab33 179 pwm->MATCHREL1 = pulsewidth_ticks - 1;
be_bryan 0:b74591d5ab33 180
be_bryan 0:b74591d5ab33 181 // Un-halt the timer and ensure the new period & pulse-width take immediate effect if necessary
be_bryan 0:b74591d5ab33 182 if (pwm->CTRL & (1 << 2)) {
be_bryan 0:b74591d5ab33 183 pwm->MATCH0 = pwm->MATCHREL0;
be_bryan 0:b74591d5ab33 184 pwm->MATCH1 = pwm->MATCHREL1;
be_bryan 0:b74591d5ab33 185 pwm->CTRL &= ~(1 << 2);
be_bryan 0:b74591d5ab33 186 }
be_bryan 0:b74591d5ab33 187 } else {
be_bryan 0:b74591d5ab33 188 // Halt the timer and force the output low
be_bryan 0:b74591d5ab33 189 pwm->CTRL |= (1 << 2) | (1 << 3);
be_bryan 0:b74591d5ab33 190 pwm->OUTPUT = 0x00000000;
be_bryan 0:b74591d5ab33 191
be_bryan 0:b74591d5ab33 192 // Ensure the new period will take immediate effect when the timer is un-halted
be_bryan 0:b74591d5ab33 193 pwm->MATCH0 = pwm->MATCHREL0;
be_bryan 0:b74591d5ab33 194 }
be_bryan 0:b74591d5ab33 195 }
be_bryan 0:b74591d5ab33 196
be_bryan 0:b74591d5ab33 197 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
be_bryan 0:b74591d5ab33 198 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
be_bryan 0:b74591d5ab33 199 }
be_bryan 0:b74591d5ab33 200
be_bryan 0:b74591d5ab33 201 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
be_bryan 0:b74591d5ab33 202 pwmout_pulsewidth_us(obj, ms * 1000);
be_bryan 0:b74591d5ab33 203 }
be_bryan 0:b74591d5ab33 204
be_bryan 0:b74591d5ab33 205 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
be_bryan 0:b74591d5ab33 206 LPC_SCT0_Type* pwm = obj->pwm;
be_bryan 0:b74591d5ab33 207 if (us > 0) {
be_bryan 0:b74591d5ab33 208 pwm->MATCHREL1 = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000) - 1;
be_bryan 0:b74591d5ab33 209
be_bryan 0:b74591d5ab33 210 // Un-halt the timer and ensure the new pulse-width takes immediate effect if necessary
be_bryan 0:b74591d5ab33 211 if (pwm->CTRL & (1 << 2)) {
be_bryan 0:b74591d5ab33 212 pwm->MATCH1 = pwm->MATCHREL1;
be_bryan 0:b74591d5ab33 213 pwm->CTRL &= ~(1 << 2);
be_bryan 0:b74591d5ab33 214 }
be_bryan 0:b74591d5ab33 215 } else {
be_bryan 0:b74591d5ab33 216 // Halt the timer and force the output low
be_bryan 0:b74591d5ab33 217 pwm->CTRL |= (1 << 2) | (1 << 3);
be_bryan 0:b74591d5ab33 218 pwm->OUTPUT = 0x00000000;
be_bryan 0:b74591d5ab33 219 }
be_bryan 0:b74591d5ab33 220 }
be_bryan 0:b74591d5ab33 221
be_bryan 0:b74591d5ab33 222 #endif