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targets/hal/TARGET_NXP/TARGET_LPC11U6X/pwmout_api.c@636:b0d178e9fa10, 2016-07-07 (annotated)

Committer:
lzbpli
Date:
Thu Jul 07 06:48:59 2016 +0000
Revision:
636:b0d178e9fa10
Parent:
516:b3fb5c6901a6 
l053

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 193:cff126de7aaf 1 /* mbed Microcontroller Library
mbed_official 193:cff126de7aaf 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 193:cff126de7aaf 3 *
mbed_official 193:cff126de7aaf 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 193:cff126de7aaf 5 * you may not use this file except in compliance with the License.
mbed_official 193:cff126de7aaf 6 * You may obtain a copy of the License at
mbed_official 193:cff126de7aaf 7 *
mbed_official 193:cff126de7aaf 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 193:cff126de7aaf 9 *
mbed_official 193:cff126de7aaf 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 193:cff126de7aaf 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 193:cff126de7aaf 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 193:cff126de7aaf 13 * See the License for the specific language governing permissions and
mbed_official 193:cff126de7aaf 14 * limitations under the License.
mbed_official 193:cff126de7aaf 15 */
mbed_official 193:cff126de7aaf 16
mbed_official 193:cff126de7aaf 17 #include "pwmout_api.h"
mbed_official 193:cff126de7aaf 18 #include "cmsis.h"
mbed_official 193:cff126de7aaf 19 #include "pinmap.h"
mbed_official 285:31249416b6f9 20 #include "mbed_error.h"
mbed_official 193:cff126de7aaf 21
mbed_official 193:cff126de7aaf 22 #if DEVICE_PWMOUT
mbed_official 193:cff126de7aaf 23
mbed_official 193:cff126de7aaf 24 #define SCT_CHANNELS 2
mbed_official 193:cff126de7aaf 25
mbed_official 193:cff126de7aaf 26 static const PinMap PinMap_PWM[] = {
mbed_official 193:cff126de7aaf 27 {P1_19, SCT0_0, 2},
mbed_official 193:cff126de7aaf 28 {P2_2 , SCT0_1, 3},
mbed_official 193:cff126de7aaf 29 {P2_7 , SCT0_2, 2},
mbed_official 193:cff126de7aaf 30 {P1_13, SCT0_3, 2},
mbed_official 193:cff126de7aaf 31 {P2_16, SCT1_0, 1},
mbed_official 193:cff126de7aaf 32 {P2_17, SCT1_1, 1},
mbed_official 193:cff126de7aaf 33 {P2_18, SCT1_2, 1},
mbed_official 193:cff126de7aaf 34 {P2_19, SCT1_3, 1},
mbed_official 193:cff126de7aaf 35 {NC , NC ,0}
mbed_official 193:cff126de7aaf 36 };
mbed_official 193:cff126de7aaf 37
mbed_official 193:cff126de7aaf 38
mbed_official 193:cff126de7aaf 39 static LPC_SCT0_Type *SCTs[SCT_CHANNELS] = {
mbed_official 193:cff126de7aaf 40 (LPC_SCT0_Type*)LPC_SCT0,
mbed_official 193:cff126de7aaf 41 (LPC_SCT0_Type*)LPC_SCT1,
mbed_official 193:cff126de7aaf 42
mbed_official 193:cff126de7aaf 43 };
mbed_official 193:cff126de7aaf 44
mbed_official 193:cff126de7aaf 45 // bit flags for used SCTs
mbed_official 193:cff126de7aaf 46 static unsigned char sct_used = 0;
mbed_official 193:cff126de7aaf 47
mbed_official 193:cff126de7aaf 48 static int get_available_sct(void) {
mbed_official 193:cff126de7aaf 49 int i;
mbed_official 193:cff126de7aaf 50 for (i=0; i<SCT_CHANNELS; i++) {
mbed_official 193:cff126de7aaf 51 if ((sct_used & (1 << i)) == 0)
mbed_official 193:cff126de7aaf 52 return i;
mbed_official 193:cff126de7aaf 53 }
mbed_official 193:cff126de7aaf 54 return -1;
mbed_official 193:cff126de7aaf 55 }
mbed_official 193:cff126de7aaf 56
mbed_official 193:cff126de7aaf 57 void pwmout_init(pwmout_t* obj, PinName pin) {
mbed_official 193:cff126de7aaf 58 // determine the SPI to use
mbed_official 193:cff126de7aaf 59 PWMName pwm_mapped = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
mbed_official 234:37acebda271b 60 if (pwm_mapped == (PWMName)NC) {
mbed_official 193:cff126de7aaf 61 error("PwmOut pin mapping failed");
mbed_official 193:cff126de7aaf 62 }
mbed_official 193:cff126de7aaf 63 int sct_n = get_available_sct();
mbed_official 193:cff126de7aaf 64 if (sct_n == -1) {
mbed_official 193:cff126de7aaf 65 error("No available SCT");
mbed_official 193:cff126de7aaf 66 }
mbed_official 193:cff126de7aaf 67
mbed_official 193:cff126de7aaf 68 sct_used |= (1 << sct_n);
mbed_official 193:cff126de7aaf 69 obj->pwm = SCTs[sct_n];
mbed_official 193:cff126de7aaf 70 obj->pwm_ch = sct_n;
mbed_official 193:cff126de7aaf 71
mbed_official 193:cff126de7aaf 72 // Enable the SCT clock
mbed_official 193:cff126de7aaf 73 LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 31);
mbed_official 193:cff126de7aaf 74
mbed_official 193:cff126de7aaf 75 // Clear peripheral reset the SCT:
mbed_official 193:cff126de7aaf 76 LPC_SYSCON->PRESETCTRL |= (1 << (obj->pwm_ch + 9));
mbed_official 193:cff126de7aaf 77 pinmap_pinout(pin, PinMap_PWM);
mbed_official 193:cff126de7aaf 78 LPC_SCT0_Type* pwm = obj->pwm;
mbed_official 193:cff126de7aaf 79
mbed_official 516:b3fb5c6901a6 80 // Unified 32-bit counter, autolimit
mbed_official 516:b3fb5c6901a6 81 pwm->CONFIG |= ((0x3 << 17) | 0x01);
mbed_official 193:cff126de7aaf 82
mbed_official 193:cff126de7aaf 83 // halt and clear the counter
mbed_official 193:cff126de7aaf 84 pwm->CTRL |= (1 << 2) | (1 << 3);
mbed_official 193:cff126de7aaf 85
mbed_official 193:cff126de7aaf 86 // System Clock -> us_ticker (1)MHz
mbed_official 193:cff126de7aaf 87 pwm->CTRL &= ~(0x7F << 5);
mbed_official 193:cff126de7aaf 88 pwm->CTRL |= (((SystemCoreClock/1000000 - 1) & 0x7F) << 5);
mbed_official 193:cff126de7aaf 89
mbed_official 193:cff126de7aaf 90 switch(pwm_mapped) {
mbed_official 193:cff126de7aaf 91 case SCT0_0:
mbed_official 193:cff126de7aaf 92 case SCT1_0:
mbed_official 193:cff126de7aaf 93 pwm->OUT0_SET = (1 << 0); // event 0
mbed_official 193:cff126de7aaf 94 pwm->OUT0_CLR = (1 << 1); // event 1
mbed_official 193:cff126de7aaf 95 break;
mbed_official 193:cff126de7aaf 96 case SCT0_1:
mbed_official 193:cff126de7aaf 97 case SCT1_1:
mbed_official 193:cff126de7aaf 98 pwm->OUT1_SET = (1 << 0); // event 0
mbed_official 193:cff126de7aaf 99 pwm->OUT1_CLR = (1 << 1); // event 1
mbed_official 193:cff126de7aaf 100 break;
mbed_official 193:cff126de7aaf 101 case SCT0_2:
mbed_official 193:cff126de7aaf 102 case SCT1_2:
mbed_official 193:cff126de7aaf 103 pwm->OUT2_SET = (1 << 0); // event 0
mbed_official 193:cff126de7aaf 104 pwm->OUT2_CLR = (1 << 1); // event 1
mbed_official 193:cff126de7aaf 105 break;
mbed_official 193:cff126de7aaf 106 case SCT0_3:
mbed_official 193:cff126de7aaf 107 case SCT1_3:
mbed_official 193:cff126de7aaf 108 pwm->OUT3_SET = (1 << 0); // event 0
mbed_official 193:cff126de7aaf 109 pwm->OUT3_CLR = (1 << 1); // event 1
mbed_official 193:cff126de7aaf 110 break;
mbed_official 193:cff126de7aaf 111 default:
mbed_official 193:cff126de7aaf 112 break;
mbed_official 193:cff126de7aaf 113 }
mbed_official 193:cff126de7aaf 114 // Event 0 : MATCH and MATCHSEL=0
mbed_official 193:cff126de7aaf 115 pwm->EV0_CTRL = (1 << 12);
mbed_official 193:cff126de7aaf 116 pwm->EV0_STATE = 0xFFFFFFFF;
mbed_official 193:cff126de7aaf 117 // Event 1 : MATCH and MATCHSEL=1
mbed_official 193:cff126de7aaf 118 pwm->EV1_CTRL = (1 << 12) | (1 << 0);
mbed_official 193:cff126de7aaf 119 pwm->EV1_STATE = 0xFFFFFFFF;
mbed_official 193:cff126de7aaf 120
mbed_official 193:cff126de7aaf 121 // Match reload register
mbed_official 193:cff126de7aaf 122 pwm->MATCHREL0 = 20000; // 20ms
mbed_official 193:cff126de7aaf 123 pwm->MATCHREL1 = (pwm->MATCHREL0 / 4); // 50% duty
mbed_official 193:cff126de7aaf 124
mbed_official 193:cff126de7aaf 125 // unhalt the counter:
mbed_official 193:cff126de7aaf 126 // - clearing bit 2 of the CTRL register
mbed_official 193:cff126de7aaf 127 pwm->CTRL &= ~(1 << 2);
mbed_official 193:cff126de7aaf 128
mbed_official 193:cff126de7aaf 129 // default to 20ms: standard for servos, and fine for e.g. brightness control
mbed_official 193:cff126de7aaf 130 pwmout_period_ms(obj, 20);
mbed_official 193:cff126de7aaf 131 pwmout_write (obj, 0);
mbed_official 193:cff126de7aaf 132 }
mbed_official 193:cff126de7aaf 133
mbed_official 193:cff126de7aaf 134 void pwmout_free(pwmout_t* obj) {
mbed_official 193:cff126de7aaf 135 sct_used &= ~(1 << obj->pwm_ch);
mbed_official 193:cff126de7aaf 136 if (sct_used == 0) {
mbed_official 193:cff126de7aaf 137 // Disable the SCT clock
mbed_official 193:cff126de7aaf 138 LPC_SYSCON->SYSAHBCLKCTRL &= ~(1UL << 31);
mbed_official 193:cff126de7aaf 139 }
mbed_official 193:cff126de7aaf 140 }
mbed_official 193:cff126de7aaf 141
mbed_official 193:cff126de7aaf 142 void pwmout_write(pwmout_t* obj, float value) {
mbed_official 193:cff126de7aaf 143 if (value < 0.0f) {
mbed_official 193:cff126de7aaf 144 value = 0.0;
mbed_official 193:cff126de7aaf 145 } else if (value > 1.0f) {
mbed_official 193:cff126de7aaf 146 value = 1.0;
mbed_official 193:cff126de7aaf 147 }
mbed_official 193:cff126de7aaf 148 uint32_t t_on = (uint32_t)((float)(obj->pwm->MATCHREL0) * value);
mbed_official 193:cff126de7aaf 149 obj->pwm->MATCHREL1 = t_on;
mbed_official 193:cff126de7aaf 150 }
mbed_official 193:cff126de7aaf 151
mbed_official 193:cff126de7aaf 152 float pwmout_read(pwmout_t* obj) {
mbed_official 193:cff126de7aaf 153 uint32_t t_off = obj->pwm->MATCHREL0;
mbed_official 193:cff126de7aaf 154 uint32_t t_on = obj->pwm->MATCHREL1;
mbed_official 193:cff126de7aaf 155 float v = (float)t_on/(float)t_off;
mbed_official 193:cff126de7aaf 156 return (v > 1.0f) ? (1.0f) : (v);
mbed_official 193:cff126de7aaf 157 }
mbed_official 193:cff126de7aaf 158
mbed_official 193:cff126de7aaf 159 void pwmout_period(pwmout_t* obj, float seconds) {
mbed_official 193:cff126de7aaf 160 pwmout_period_us(obj, seconds * 1000000.0f);
mbed_official 193:cff126de7aaf 161 }
mbed_official 193:cff126de7aaf 162
mbed_official 193:cff126de7aaf 163 void pwmout_period_ms(pwmout_t* obj, int ms) {
mbed_official 193:cff126de7aaf 164 pwmout_period_us(obj, ms * 1000);
mbed_official 193:cff126de7aaf 165 }
mbed_official 193:cff126de7aaf 166
mbed_official 193:cff126de7aaf 167 // Set the PWM period, keeping the duty cycle the same.
mbed_official 193:cff126de7aaf 168 void pwmout_period_us(pwmout_t* obj, int us) {
mbed_official 193:cff126de7aaf 169 uint32_t t_off = obj->pwm->MATCHREL0;
mbed_official 193:cff126de7aaf 170 uint32_t t_on = obj->pwm->MATCHREL1;
mbed_official 193:cff126de7aaf 171 float v = (float)t_on/(float)t_off;
mbed_official 516:b3fb5c6901a6 172 obj->pwm->MATCHREL0 = (uint32_t)us;
mbed_official 516:b3fb5c6901a6 173 obj->pwm->MATCHREL1 = (uint32_t)((float)us * (float)v);
mbed_official 193:cff126de7aaf 174 }
mbed_official 193:cff126de7aaf 175
mbed_official 193:cff126de7aaf 176 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
mbed_official 193:cff126de7aaf 177 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
mbed_official 193:cff126de7aaf 178 }
mbed_official 193:cff126de7aaf 179
mbed_official 193:cff126de7aaf 180 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
mbed_official 193:cff126de7aaf 181 pwmout_pulsewidth_us(obj, ms * 1000);
mbed_official 193:cff126de7aaf 182 }
mbed_official 193:cff126de7aaf 183
mbed_official 193:cff126de7aaf 184 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
mbed_official 516:b3fb5c6901a6 185 obj->pwm->MATCHREL1 = (uint32_t)us;
mbed_official 193:cff126de7aaf 186 }
mbed_official 193:cff126de7aaf 187
mbed_official 193:cff126de7aaf 188 #endif