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targets/hal/TARGET_NXP/TARGET_LPC11U6X/pwmout_api.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Child:
57:791e51e3acc9
Initial commit on mbed-dev



Replaces mbed-src (now inactive)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 0:9b334a45a8ff 1 /* mbed Microcontroller Library
bogdanm 0:9b334a45a8ff 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 0:9b334a45a8ff 3 *
bogdanm 0:9b334a45a8ff 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 0:9b334a45a8ff 5 * you may not use this file except in compliance with the License.
bogdanm 0:9b334a45a8ff 6 * You may obtain a copy of the License at
bogdanm 0:9b334a45a8ff 7 *
bogdanm 0:9b334a45a8ff 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 0:9b334a45a8ff 9 *
bogdanm 0:9b334a45a8ff 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 0:9b334a45a8ff 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 0:9b334a45a8ff 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 0:9b334a45a8ff 13 * See the License for the specific language governing permissions and
bogdanm 0:9b334a45a8ff 14 * limitations under the License.
bogdanm 0:9b334a45a8ff 15 */
bogdanm 0:9b334a45a8ff 16
bogdanm 0:9b334a45a8ff 17 #include "pwmout_api.h"
bogdanm 0:9b334a45a8ff 18 #include "cmsis.h"
bogdanm 0:9b334a45a8ff 19 #include "pinmap.h"
bogdanm 0:9b334a45a8ff 20 #include "mbed_error.h"
bogdanm 0:9b334a45a8ff 21
bogdanm 0:9b334a45a8ff 22 #if DEVICE_PWMOUT
bogdanm 0:9b334a45a8ff 23
bogdanm 0:9b334a45a8ff 24 #define SCT_CHANNELS 2
bogdanm 0:9b334a45a8ff 25
bogdanm 0:9b334a45a8ff 26 static const PinMap PinMap_PWM[] = {
bogdanm 0:9b334a45a8ff 27 {P1_19, SCT0_0, 2},
bogdanm 0:9b334a45a8ff 28 {P2_2 , SCT0_1, 3},
bogdanm 0:9b334a45a8ff 29 {P2_7 , SCT0_2, 2},
bogdanm 0:9b334a45a8ff 30 {P1_13, SCT0_3, 2},
bogdanm 0:9b334a45a8ff 31 {P2_16, SCT1_0, 1},
bogdanm 0:9b334a45a8ff 32 {P2_17, SCT1_1, 1},
bogdanm 0:9b334a45a8ff 33 {P2_18, SCT1_2, 1},
bogdanm 0:9b334a45a8ff 34 {P2_19, SCT1_3, 1},
bogdanm 0:9b334a45a8ff 35 {NC , NC ,0}
bogdanm 0:9b334a45a8ff 36 };
bogdanm 0:9b334a45a8ff 37
bogdanm 0:9b334a45a8ff 38
bogdanm 0:9b334a45a8ff 39 static LPC_SCT0_Type *SCTs[SCT_CHANNELS] = {
bogdanm 0:9b334a45a8ff 40 (LPC_SCT0_Type*)LPC_SCT0,
bogdanm 0:9b334a45a8ff 41 (LPC_SCT0_Type*)LPC_SCT1,
bogdanm 0:9b334a45a8ff 42
bogdanm 0:9b334a45a8ff 43 };
bogdanm 0:9b334a45a8ff 44
bogdanm 0:9b334a45a8ff 45 // bit flags for used SCTs
bogdanm 0:9b334a45a8ff 46 static unsigned char sct_used = 0;
bogdanm 0:9b334a45a8ff 47
bogdanm 0:9b334a45a8ff 48 static int get_available_sct(void) {
bogdanm 0:9b334a45a8ff 49 int i;
bogdanm 0:9b334a45a8ff 50 for (i=0; i<SCT_CHANNELS; i++) {
bogdanm 0:9b334a45a8ff 51 if ((sct_used & (1 << i)) == 0)
bogdanm 0:9b334a45a8ff 52 return i;
bogdanm 0:9b334a45a8ff 53 }
bogdanm 0:9b334a45a8ff 54 return -1;
bogdanm 0:9b334a45a8ff 55 }
bogdanm 0:9b334a45a8ff 56
bogdanm 0:9b334a45a8ff 57 void pwmout_init(pwmout_t* obj, PinName pin) {
bogdanm 0:9b334a45a8ff 58 // determine the SPI to use
bogdanm 0:9b334a45a8ff 59 PWMName pwm_mapped = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
bogdanm 0:9b334a45a8ff 60 if (pwm_mapped == (PWMName)NC) {
bogdanm 0:9b334a45a8ff 61 error("PwmOut pin mapping failed");
bogdanm 0:9b334a45a8ff 62 }
bogdanm 0:9b334a45a8ff 63 int sct_n = get_available_sct();
bogdanm 0:9b334a45a8ff 64 if (sct_n == -1) {
bogdanm 0:9b334a45a8ff 65 error("No available SCT");
bogdanm 0:9b334a45a8ff 66 }
bogdanm 0:9b334a45a8ff 67
bogdanm 0:9b334a45a8ff 68 sct_used |= (1 << sct_n);
bogdanm 0:9b334a45a8ff 69 obj->pwm = SCTs[sct_n];
bogdanm 0:9b334a45a8ff 70 obj->pwm_ch = sct_n;
bogdanm 0:9b334a45a8ff 71
bogdanm 0:9b334a45a8ff 72 // Enable the SCT clock
bogdanm 0:9b334a45a8ff 73 LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 31);
bogdanm 0:9b334a45a8ff 74
bogdanm 0:9b334a45a8ff 75 // Clear peripheral reset the SCT:
bogdanm 0:9b334a45a8ff 76 LPC_SYSCON->PRESETCTRL |= (1 << (obj->pwm_ch + 9));
bogdanm 0:9b334a45a8ff 77 pinmap_pinout(pin, PinMap_PWM);
bogdanm 0:9b334a45a8ff 78 LPC_SCT0_Type* pwm = obj->pwm;
bogdanm 0:9b334a45a8ff 79
bogdanm 0:9b334a45a8ff 80 // Unified 32-bit counter, autolimit
bogdanm 0:9b334a45a8ff 81 pwm->CONFIG |= ((0x3 << 17) | 0x01);
bogdanm 0:9b334a45a8ff 82
bogdanm 0:9b334a45a8ff 83 // halt and clear the counter
bogdanm 0:9b334a45a8ff 84 pwm->CTRL |= (1 << 2) | (1 << 3);
bogdanm 0:9b334a45a8ff 85
bogdanm 0:9b334a45a8ff 86 // System Clock -> us_ticker (1)MHz
bogdanm 0:9b334a45a8ff 87 pwm->CTRL &= ~(0x7F << 5);
bogdanm 0:9b334a45a8ff 88 pwm->CTRL |= (((SystemCoreClock/1000000 - 1) & 0x7F) << 5);
bogdanm 0:9b334a45a8ff 89
bogdanm 0:9b334a45a8ff 90 switch(pwm_mapped) {
bogdanm 0:9b334a45a8ff 91 case SCT0_0:
bogdanm 0:9b334a45a8ff 92 case SCT1_0:
bogdanm 0:9b334a45a8ff 93 pwm->OUT0_SET = (1 << 0); // event 0
bogdanm 0:9b334a45a8ff 94 pwm->OUT0_CLR = (1 << 1); // event 1
bogdanm 0:9b334a45a8ff 95 break;
bogdanm 0:9b334a45a8ff 96 case SCT0_1:
bogdanm 0:9b334a45a8ff 97 case SCT1_1:
bogdanm 0:9b334a45a8ff 98 pwm->OUT1_SET = (1 << 0); // event 0
bogdanm 0:9b334a45a8ff 99 pwm->OUT1_CLR = (1 << 1); // event 1
bogdanm 0:9b334a45a8ff 100 break;
bogdanm 0:9b334a45a8ff 101 case SCT0_2:
bogdanm 0:9b334a45a8ff 102 case SCT1_2:
bogdanm 0:9b334a45a8ff 103 pwm->OUT2_SET = (1 << 0); // event 0
bogdanm 0:9b334a45a8ff 104 pwm->OUT2_CLR = (1 << 1); // event 1
bogdanm 0:9b334a45a8ff 105 break;
bogdanm 0:9b334a45a8ff 106 case SCT0_3:
bogdanm 0:9b334a45a8ff 107 case SCT1_3:
bogdanm 0:9b334a45a8ff 108 pwm->OUT3_SET = (1 << 0); // event 0
bogdanm 0:9b334a45a8ff 109 pwm->OUT3_CLR = (1 << 1); // event 1
bogdanm 0:9b334a45a8ff 110 break;
bogdanm 0:9b334a45a8ff 111 default:
bogdanm 0:9b334a45a8ff 112 break;
bogdanm 0:9b334a45a8ff 113 }
bogdanm 0:9b334a45a8ff 114 // Event 0 : MATCH and MATCHSEL=0
bogdanm 0:9b334a45a8ff 115 pwm->EV0_CTRL = (1 << 12);
bogdanm 0:9b334a45a8ff 116 pwm->EV0_STATE = 0xFFFFFFFF;
bogdanm 0:9b334a45a8ff 117 // Event 1 : MATCH and MATCHSEL=1
bogdanm 0:9b334a45a8ff 118 pwm->EV1_CTRL = (1 << 12) | (1 << 0);
bogdanm 0:9b334a45a8ff 119 pwm->EV1_STATE = 0xFFFFFFFF;
bogdanm 0:9b334a45a8ff 120
bogdanm 0:9b334a45a8ff 121 // Match reload register
bogdanm 0:9b334a45a8ff 122 pwm->MATCHREL0 = 20000; // 20ms
bogdanm 0:9b334a45a8ff 123 pwm->MATCHREL1 = (pwm->MATCHREL0 / 4); // 50% duty
bogdanm 0:9b334a45a8ff 124
bogdanm 0:9b334a45a8ff 125 // unhalt the counter:
bogdanm 0:9b334a45a8ff 126 // - clearing bit 2 of the CTRL register
bogdanm 0:9b334a45a8ff 127 pwm->CTRL &= ~(1 << 2);
bogdanm 0:9b334a45a8ff 128
bogdanm 0:9b334a45a8ff 129 // default to 20ms: standard for servos, and fine for e.g. brightness control
bogdanm 0:9b334a45a8ff 130 pwmout_period_ms(obj, 20);
bogdanm 0:9b334a45a8ff 131 pwmout_write (obj, 0);
bogdanm 0:9b334a45a8ff 132 }
bogdanm 0:9b334a45a8ff 133
bogdanm 0:9b334a45a8ff 134 void pwmout_free(pwmout_t* obj) {
bogdanm 0:9b334a45a8ff 135 sct_used &= ~(1 << obj->pwm_ch);
bogdanm 0:9b334a45a8ff 136 if (sct_used == 0) {
bogdanm 0:9b334a45a8ff 137 // Disable the SCT clock
bogdanm 0:9b334a45a8ff 138 LPC_SYSCON->SYSAHBCLKCTRL &= ~(1UL << 31);
bogdanm 0:9b334a45a8ff 139 }
bogdanm 0:9b334a45a8ff 140 }
bogdanm 0:9b334a45a8ff 141
bogdanm 0:9b334a45a8ff 142 void pwmout_write(pwmout_t* obj, float value) {
bogdanm 0:9b334a45a8ff 143 if (value < 0.0f) {
bogdanm 0:9b334a45a8ff 144 value = 0.0;
bogdanm 0:9b334a45a8ff 145 } else if (value > 1.0f) {
bogdanm 0:9b334a45a8ff 146 value = 1.0;
bogdanm 0:9b334a45a8ff 147 }
bogdanm 0:9b334a45a8ff 148 uint32_t t_on = (uint32_t)((float)(obj->pwm->MATCHREL0) * value);
bogdanm 0:9b334a45a8ff 149 obj->pwm->MATCHREL1 = t_on;
bogdanm 0:9b334a45a8ff 150 }
bogdanm 0:9b334a45a8ff 151
bogdanm 0:9b334a45a8ff 152 float pwmout_read(pwmout_t* obj) {
bogdanm 0:9b334a45a8ff 153 uint32_t t_off = obj->pwm->MATCHREL0;
bogdanm 0:9b334a45a8ff 154 uint32_t t_on = obj->pwm->MATCHREL1;
bogdanm 0:9b334a45a8ff 155 float v = (float)t_on/(float)t_off;
bogdanm 0:9b334a45a8ff 156 return (v > 1.0f) ? (1.0f) : (v);
bogdanm 0:9b334a45a8ff 157 }
bogdanm 0:9b334a45a8ff 158
bogdanm 0:9b334a45a8ff 159 void pwmout_period(pwmout_t* obj, float seconds) {
bogdanm 0:9b334a45a8ff 160 pwmout_period_us(obj, seconds * 1000000.0f);
bogdanm 0:9b334a45a8ff 161 }
bogdanm 0:9b334a45a8ff 162
bogdanm 0:9b334a45a8ff 163 void pwmout_period_ms(pwmout_t* obj, int ms) {
bogdanm 0:9b334a45a8ff 164 pwmout_period_us(obj, ms * 1000);
bogdanm 0:9b334a45a8ff 165 }
bogdanm 0:9b334a45a8ff 166
bogdanm 0:9b334a45a8ff 167 // Set the PWM period, keeping the duty cycle the same.
bogdanm 0:9b334a45a8ff 168 void pwmout_period_us(pwmout_t* obj, int us) {
bogdanm 0:9b334a45a8ff 169 uint32_t t_off = obj->pwm->MATCHREL0;
bogdanm 0:9b334a45a8ff 170 uint32_t t_on = obj->pwm->MATCHREL1;
bogdanm 0:9b334a45a8ff 171 float v = (float)t_on/(float)t_off;
bogdanm 0:9b334a45a8ff 172 obj->pwm->MATCHREL0 = (uint32_t)us;
bogdanm 0:9b334a45a8ff 173 obj->pwm->MATCHREL1 = (uint32_t)((float)us * (float)v);
bogdanm 0:9b334a45a8ff 174 }
bogdanm 0:9b334a45a8ff 175
bogdanm 0:9b334a45a8ff 176 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
bogdanm 0:9b334a45a8ff 177 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
bogdanm 0:9b334a45a8ff 178 }
bogdanm 0:9b334a45a8ff 179
bogdanm 0:9b334a45a8ff 180 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
bogdanm 0:9b334a45a8ff 181 pwmout_pulsewidth_us(obj, ms * 1000);
bogdanm 0:9b334a45a8ff 182 }
bogdanm 0:9b334a45a8ff 183
bogdanm 0:9b334a45a8ff 184 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
bogdanm 0:9b334a45a8ff 185 obj->pwm->MATCHREL1 = (uint32_t)us;
bogdanm 0:9b334a45a8ff 186 }
bogdanm 0:9b334a45a8ff 187
bogdanm 0:9b334a45a8ff 188 #endif