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Last commit 20 Feb 2019 by mbed official

vendor/NXP/LPC4088/hal/pwmout_api.c@10:3bc89ef62ce7, 2013-06-14 (annotated)

Committer:
emilmont
Date:
Fri Jun 14 17:49:17 2013 +0100
Revision:
10:3bc89ef62ce7
Unify mbed library sources

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 10:3bc89ef62ce7 1 /* mbed Microcontroller Library
emilmont 10:3bc89ef62ce7 2 * Copyright (c) 2006-2013 ARM Limited
emilmont 10:3bc89ef62ce7 3 *
emilmont 10:3bc89ef62ce7 4 * Licensed under the Apache License, Version 2.0 (the "License");
emilmont 10:3bc89ef62ce7 5 * you may not use this file except in compliance with the License.
emilmont 10:3bc89ef62ce7 6 * You may obtain a copy of the License at
emilmont 10:3bc89ef62ce7 7 *
emilmont 10:3bc89ef62ce7 8 * http://www.apache.org/licenses/LICENSE-2.0
emilmont 10:3bc89ef62ce7 9 *
emilmont 10:3bc89ef62ce7 10 * Unless required by applicable law or agreed to in writing, software
emilmont 10:3bc89ef62ce7 11 * distributed under the License is distributed on an "AS IS" BASIS,
emilmont 10:3bc89ef62ce7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
emilmont 10:3bc89ef62ce7 13 * See the License for the specific language governing permissions and
emilmont 10:3bc89ef62ce7 14 * limitations under the License.
emilmont 10:3bc89ef62ce7 15 */
emilmont 10:3bc89ef62ce7 16 #include "pwmout_api.h"
emilmont 10:3bc89ef62ce7 17 #include "cmsis.h"
emilmont 10:3bc89ef62ce7 18 #include "pinmap.h"
emilmont 10:3bc89ef62ce7 19 #include "error.h"
emilmont 10:3bc89ef62ce7 20
emilmont 10:3bc89ef62ce7 21 #define TCR_CNT_EN 0x00000001
emilmont 10:3bc89ef62ce7 22 #define TCR_RESET 0x00000002
emilmont 10:3bc89ef62ce7 23
emilmont 10:3bc89ef62ce7 24 // PORT ID, PWM ID, Pin function
emilmont 10:3bc89ef62ce7 25 static const PinMap PinMap_PWM[] = {
emilmont 10:3bc89ef62ce7 26 {P1_2, PWM0_1, 3},
emilmont 10:3bc89ef62ce7 27 {P1_3, PWM0_2, 3},
emilmont 10:3bc89ef62ce7 28 {P1_5, PWM0_3, 3},
emilmont 10:3bc89ef62ce7 29 {P1_6, PWM0_4, 3},
emilmont 10:3bc89ef62ce7 30 {P1_7, PWM0_5, 3},
emilmont 10:3bc89ef62ce7 31 {P1_11, PWM0_6, 3},
emilmont 10:3bc89ef62ce7 32 {P1_18, PWM1_1, 2},
emilmont 10:3bc89ef62ce7 33 {P1_20, PWM1_2, 2},
emilmont 10:3bc89ef62ce7 34 {P1_21, PWM1_3, 2},
emilmont 10:3bc89ef62ce7 35 {P1_23, PWM1_4, 2},
emilmont 10:3bc89ef62ce7 36 {P1_24, PWM1_5, 2},
emilmont 10:3bc89ef62ce7 37 {P1_26, PWM1_6, 2},
emilmont 10:3bc89ef62ce7 38 {P2_0, PWM1_1, 1},
emilmont 10:3bc89ef62ce7 39 {P2_1, PWM1_2, 1},
emilmont 10:3bc89ef62ce7 40 {P2_2, PWM1_3, 1},
emilmont 10:3bc89ef62ce7 41 {P2_3, PWM1_4, 1},
emilmont 10:3bc89ef62ce7 42 {P2_4, PWM1_5, 1},
emilmont 10:3bc89ef62ce7 43 {P2_5, PWM1_6, 1},
emilmont 10:3bc89ef62ce7 44 {P3_16, PWM0_1, 2},
emilmont 10:3bc89ef62ce7 45 {P3_17, PWM0_2, 2},
emilmont 10:3bc89ef62ce7 46 {P3_18, PWM0_3, 2},
emilmont 10:3bc89ef62ce7 47 {P3_19, PWM0_4, 2},
emilmont 10:3bc89ef62ce7 48 {P3_20, PWM0_5, 2},
emilmont 10:3bc89ef62ce7 49 {P3_21, PWM0_6, 2},
emilmont 10:3bc89ef62ce7 50 {P3_24, PWM1_1, 2},
emilmont 10:3bc89ef62ce7 51 {P3_25, PWM1_2, 2},
emilmont 10:3bc89ef62ce7 52 {P3_26, PWM1_3, 2},
emilmont 10:3bc89ef62ce7 53 {P3_27, PWM1_4, 2},
emilmont 10:3bc89ef62ce7 54 {P3_28, PWM1_5, 2},
emilmont 10:3bc89ef62ce7 55 {P3_29, PWM1_6, 2},
emilmont 10:3bc89ef62ce7 56 {NC, NC, 0}
emilmont 10:3bc89ef62ce7 57 };
emilmont 10:3bc89ef62ce7 58
emilmont 10:3bc89ef62ce7 59 static const uint32_t PWM_mr_offset[7] = {
emilmont 10:3bc89ef62ce7 60 0x18, 0x1C, 0x20, 0x24, 0x40, 0x44, 0x48
emilmont 10:3bc89ef62ce7 61 };
emilmont 10:3bc89ef62ce7 62
emilmont 10:3bc89ef62ce7 63 #define TCR_PWM_EN 0x00000008
emilmont 10:3bc89ef62ce7 64 static unsigned int pwm_clock_mhz;
emilmont 10:3bc89ef62ce7 65
emilmont 10:3bc89ef62ce7 66 void pwmout_init(pwmout_t* obj, PinName pin) {
emilmont 10:3bc89ef62ce7 67 // determine the channel
emilmont 10:3bc89ef62ce7 68 PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
emilmont 10:3bc89ef62ce7 69 if (pwm == (uint32_t)NC)
emilmont 10:3bc89ef62ce7 70 error("PwmOut pin mapping failed");
emilmont 10:3bc89ef62ce7 71
emilmont 10:3bc89ef62ce7 72 obj->channel = pwm;
emilmont 10:3bc89ef62ce7 73 obj->pwm = LPC_PWM0;
emilmont 10:3bc89ef62ce7 74
emilmont 10:3bc89ef62ce7 75 if (obj->channel > 6) { // PWM1 is used if pwm > 6
emilmont 10:3bc89ef62ce7 76 obj->channel -= 6;
emilmont 10:3bc89ef62ce7 77 obj->pwm = LPC_PWM1;
emilmont 10:3bc89ef62ce7 78 }
emilmont 10:3bc89ef62ce7 79
emilmont 10:3bc89ef62ce7 80 obj->MR = (__IO uint32_t *)((uint32_t)obj->pwm + PWM_mr_offset[obj->channel]);
emilmont 10:3bc89ef62ce7 81
emilmont 10:3bc89ef62ce7 82 // ensure the power is on
emilmont 10:3bc89ef62ce7 83 if (obj->pwm == LPC_PWM0) {
emilmont 10:3bc89ef62ce7 84 LPC_SC->PCONP |= 1 << 5;
emilmont 10:3bc89ef62ce7 85 } else {
emilmont 10:3bc89ef62ce7 86 LPC_SC->PCONP |= 1 << 6;
emilmont 10:3bc89ef62ce7 87 }
emilmont 10:3bc89ef62ce7 88
emilmont 10:3bc89ef62ce7 89 obj->pwm->PR = 0; // no pre-scale
emilmont 10:3bc89ef62ce7 90
emilmont 10:3bc89ef62ce7 91 // ensure single PWM mode
emilmont 10:3bc89ef62ce7 92 obj->pwm->MCR = 1 << 1; // reset TC on match 0
emilmont 10:3bc89ef62ce7 93
emilmont 10:3bc89ef62ce7 94 // enable the specific PWM output
emilmont 10:3bc89ef62ce7 95 obj->pwm->PCR |= 1 << (8 + obj->channel);
emilmont 10:3bc89ef62ce7 96
emilmont 10:3bc89ef62ce7 97 pwm_clock_mhz = PeripheralClock / 1000000;
emilmont 10:3bc89ef62ce7 98
emilmont 10:3bc89ef62ce7 99 // default to 20ms: standard for servos, and fine for e.g. brightness control
emilmont 10:3bc89ef62ce7 100 pwmout_period_ms(obj, 20);
emilmont 10:3bc89ef62ce7 101 pwmout_write (obj, 0);
emilmont 10:3bc89ef62ce7 102
emilmont 10:3bc89ef62ce7 103 // Wire pinout
emilmont 10:3bc89ef62ce7 104 pinmap_pinout(pin, PinMap_PWM);
emilmont 10:3bc89ef62ce7 105 }
emilmont 10:3bc89ef62ce7 106
emilmont 10:3bc89ef62ce7 107 void pwmout_free(pwmout_t* obj) {
emilmont 10:3bc89ef62ce7 108 // [TODO]
emilmont 10:3bc89ef62ce7 109 }
emilmont 10:3bc89ef62ce7 110
emilmont 10:3bc89ef62ce7 111 void pwmout_write(pwmout_t* obj, float value) {
emilmont 10:3bc89ef62ce7 112 if (value < 0.0f) {
emilmont 10:3bc89ef62ce7 113 value = 0.0;
emilmont 10:3bc89ef62ce7 114 } else if (value > 1.0f) {
emilmont 10:3bc89ef62ce7 115 value = 1.0;
emilmont 10:3bc89ef62ce7 116 }
emilmont 10:3bc89ef62ce7 117
emilmont 10:3bc89ef62ce7 118 // set channel match to percentage
emilmont 10:3bc89ef62ce7 119 uint32_t v = (uint32_t)((float)(obj->pwm->MR0) * value);
emilmont 10:3bc89ef62ce7 120
emilmont 10:3bc89ef62ce7 121 // workaround for PWM1[1] - Never make it equal MR0, else we get 1 cycle dropout
emilmont 10:3bc89ef62ce7 122 if (v == obj->pwm->MR0) {
emilmont 10:3bc89ef62ce7 123 v++;
emilmont 10:3bc89ef62ce7 124 }
emilmont 10:3bc89ef62ce7 125
emilmont 10:3bc89ef62ce7 126 *obj->MR = v;
emilmont 10:3bc89ef62ce7 127
emilmont 10:3bc89ef62ce7 128 // accept on next period start
emilmont 10:3bc89ef62ce7 129 obj->pwm->LER |= 1 << obj->channel;
emilmont 10:3bc89ef62ce7 130 }
emilmont 10:3bc89ef62ce7 131
emilmont 10:3bc89ef62ce7 132 float pwmout_read(pwmout_t* obj) {
emilmont 10:3bc89ef62ce7 133 float v = (float)(*obj->MR) / (float)(obj->pwm->MR0);
emilmont 10:3bc89ef62ce7 134 return (v > 1.0f) ? (1.0f) : (v);
emilmont 10:3bc89ef62ce7 135 }
emilmont 10:3bc89ef62ce7 136
emilmont 10:3bc89ef62ce7 137 void pwmout_period(pwmout_t* obj, float seconds) {
emilmont 10:3bc89ef62ce7 138 pwmout_period_us(obj, seconds * 1000000.0f);
emilmont 10:3bc89ef62ce7 139 }
emilmont 10:3bc89ef62ce7 140
emilmont 10:3bc89ef62ce7 141 void pwmout_period_ms(pwmout_t* obj, int ms) {
emilmont 10:3bc89ef62ce7 142 pwmout_period_us(obj, ms * 1000);
emilmont 10:3bc89ef62ce7 143 }
emilmont 10:3bc89ef62ce7 144
emilmont 10:3bc89ef62ce7 145 // Set the PWM period, keeping the duty cycle the same.
emilmont 10:3bc89ef62ce7 146 void pwmout_period_us(pwmout_t* obj, int us) {
emilmont 10:3bc89ef62ce7 147 // calculate number of ticks
emilmont 10:3bc89ef62ce7 148 uint32_t ticks = pwm_clock_mhz * us;
emilmont 10:3bc89ef62ce7 149
emilmont 10:3bc89ef62ce7 150 // set reset
emilmont 10:3bc89ef62ce7 151 obj->pwm->TCR = TCR_RESET;
emilmont 10:3bc89ef62ce7 152
emilmont 10:3bc89ef62ce7 153 // set the global match register
emilmont 10:3bc89ef62ce7 154 obj->pwm->MR0 = ticks;
emilmont 10:3bc89ef62ce7 155
emilmont 10:3bc89ef62ce7 156 // Scale the pulse width to preserve the duty ratio
emilmont 10:3bc89ef62ce7 157 if (obj->pwm->MR0 > 0) {
emilmont 10:3bc89ef62ce7 158 *obj->MR = (*obj->MR * ticks) / obj->pwm->MR0;
emilmont 10:3bc89ef62ce7 159 }
emilmont 10:3bc89ef62ce7 160
emilmont 10:3bc89ef62ce7 161 // set the channel latch to update value at next period start
emilmont 10:3bc89ef62ce7 162 obj->pwm->LER |= 1 << 0;
emilmont 10:3bc89ef62ce7 163
emilmont 10:3bc89ef62ce7 164 // enable counter and pwm, clear reset
emilmont 10:3bc89ef62ce7 165 obj->pwm->TCR = TCR_CNT_EN | TCR_PWM_EN;
emilmont 10:3bc89ef62ce7 166 }
emilmont 10:3bc89ef62ce7 167
emilmont 10:3bc89ef62ce7 168 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
emilmont 10:3bc89ef62ce7 169 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
emilmont 10:3bc89ef62ce7 170 }
emilmont 10:3bc89ef62ce7 171
emilmont 10:3bc89ef62ce7 172 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
emilmont 10:3bc89ef62ce7 173 pwmout_pulsewidth_us(obj, ms * 1000);
emilmont 10:3bc89ef62ce7 174 }
emilmont 10:3bc89ef62ce7 175
emilmont 10:3bc89ef62ce7 176 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
emilmont 10:3bc89ef62ce7 177 // calculate number of ticks
emilmont 10:3bc89ef62ce7 178 uint32_t v = pwm_clock_mhz * us;
emilmont 10:3bc89ef62ce7 179
emilmont 10:3bc89ef62ce7 180 // workaround for PWM1[1] - Never make it equal MR0, else we get 1 cycle dropout
emilmont 10:3bc89ef62ce7 181 if (v == obj->pwm->MR0) {
emilmont 10:3bc89ef62ce7 182 v++;
emilmont 10:3bc89ef62ce7 183 }
emilmont 10:3bc89ef62ce7 184
emilmont 10:3bc89ef62ce7 185 // set the match register value
emilmont 10:3bc89ef62ce7 186 *obj->MR = v;
emilmont 10:3bc89ef62ce7 187
emilmont 10:3bc89ef62ce7 188 // set the channel latch to update value at next period start
emilmont 10:3bc89ef62ce7 189 obj->pwm->LER |= 1 << obj->channel;
emilmont 10:3bc89ef62ce7 190 }