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targets/hal/TARGET_NXP/TARGET_LPC82X/pwmout_api.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Child:
81:8b5f63428415
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 #include "mbed_assert.h"
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 // bit flags for used SCTs
bogdanm 0:9b334a45a8ff 25 static unsigned char sct_used = 0;
bogdanm 0:9b334a45a8ff 26
bogdanm 0:9b334a45a8ff 27 static int get_available_sct()
bogdanm 0:9b334a45a8ff 28 {
bogdanm 0:9b334a45a8ff 29 int i;
bogdanm 0:9b334a45a8ff 30 for (i = 0; i < 4; i++) {
bogdanm 0:9b334a45a8ff 31 if ((sct_used & (1 << i)) == 0)
bogdanm 0:9b334a45a8ff 32 return i;
bogdanm 0:9b334a45a8ff 33 }
bogdanm 0:9b334a45a8ff 34 return -1;
bogdanm 0:9b334a45a8ff 35 }
bogdanm 0:9b334a45a8ff 36
bogdanm 0:9b334a45a8ff 37 void pwmout_init(pwmout_t* obj, PinName pin)
bogdanm 0:9b334a45a8ff 38 {
bogdanm 0:9b334a45a8ff 39 MBED_ASSERT(pin != (PinName)NC);
bogdanm 0:9b334a45a8ff 40
bogdanm 0:9b334a45a8ff 41 int sct_n = get_available_sct();
bogdanm 0:9b334a45a8ff 42 if (sct_n == -1) {
bogdanm 0:9b334a45a8ff 43 error("No available SCT");
bogdanm 0:9b334a45a8ff 44 }
bogdanm 0:9b334a45a8ff 45
bogdanm 0:9b334a45a8ff 46 sct_used |= (1 << sct_n);
bogdanm 0:9b334a45a8ff 47
bogdanm 0:9b334a45a8ff 48 obj->pwm = (LPC_SCT_Type*)LPC_SCT;
bogdanm 0:9b334a45a8ff 49 obj->pwm_ch = sct_n;
bogdanm 0:9b334a45a8ff 50
bogdanm 0:9b334a45a8ff 51 LPC_SCT_Type* pwm = obj->pwm;
bogdanm 0:9b334a45a8ff 52
bogdanm 0:9b334a45a8ff 53 // Enable the SCT clock
bogdanm 0:9b334a45a8ff 54 LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 8);
bogdanm 0:9b334a45a8ff 55
bogdanm 0:9b334a45a8ff 56 // Clear peripheral reset the SCT:
bogdanm 0:9b334a45a8ff 57 LPC_SYSCON->PRESETCTRL |= (1 << 8);
bogdanm 0:9b334a45a8ff 58
bogdanm 0:9b334a45a8ff 59 switch(sct_n) {
bogdanm 0:9b334a45a8ff 60 case 0:
bogdanm 0:9b334a45a8ff 61 // SCT_OUT0
bogdanm 0:9b334a45a8ff 62 LPC_SWM->PINASSIGN[7] &= ~0xFF000000;
bogdanm 0:9b334a45a8ff 63 LPC_SWM->PINASSIGN[7] |= ((pin >> PIN_SHIFT) << 24);
bogdanm 0:9b334a45a8ff 64 break;
bogdanm 0:9b334a45a8ff 65 case 1:
bogdanm 0:9b334a45a8ff 66 // SCT_OUT1
bogdanm 0:9b334a45a8ff 67 LPC_SWM->PINASSIGN[8] &= ~0x000000FF;
bogdanm 0:9b334a45a8ff 68 LPC_SWM->PINASSIGN[8] |= (pin >> PIN_SHIFT);
bogdanm 0:9b334a45a8ff 69 break;
bogdanm 0:9b334a45a8ff 70 case 2:
bogdanm 0:9b334a45a8ff 71 // SCT2_OUT2
bogdanm 0:9b334a45a8ff 72 LPC_SWM->PINASSIGN[8] &= ~0x0000FF00;
bogdanm 0:9b334a45a8ff 73 LPC_SWM->PINASSIGN[8] |= ((pin >> PIN_SHIFT) << 8);
bogdanm 0:9b334a45a8ff 74 break;
bogdanm 0:9b334a45a8ff 75 case 3:
bogdanm 0:9b334a45a8ff 76 // SCT3_OUT3
bogdanm 0:9b334a45a8ff 77 LPC_SWM->PINASSIGN[8] &= ~0x00FF0000;
bogdanm 0:9b334a45a8ff 78 LPC_SWM->PINASSIGN[8] |= ((pin >> PIN_SHIFT) << 16);
bogdanm 0:9b334a45a8ff 79 break;
bogdanm 0:9b334a45a8ff 80 default:
bogdanm 0:9b334a45a8ff 81 break;
bogdanm 0:9b334a45a8ff 82 }
bogdanm 0:9b334a45a8ff 83
bogdanm 0:9b334a45a8ff 84 // Unified 32-bit counter, autolimit
bogdanm 0:9b334a45a8ff 85 pwm->CONFIG |= ((0x3 << 17) | 0x01);
bogdanm 0:9b334a45a8ff 86
bogdanm 0:9b334a45a8ff 87 // halt and clear the counter
bogdanm 0:9b334a45a8ff 88 pwm->CTRL |= (1 << 2) | (1 << 3);
bogdanm 0:9b334a45a8ff 89
bogdanm 0:9b334a45a8ff 90 // System Clock -> us_ticker (1)MHz
bogdanm 0:9b334a45a8ff 91 pwm->CTRL &= ~(0x7F << 5);
bogdanm 0:9b334a45a8ff 92 pwm->CTRL |= (((SystemCoreClock/1000000 - 1) & 0x7F) << 5);
bogdanm 0:9b334a45a8ff 93
bogdanm 0:9b334a45a8ff 94 pwm->OUT[sct_n].SET = (1 << ((sct_n * 2) + 0));
bogdanm 0:9b334a45a8ff 95 pwm->OUT[sct_n].CLR = (1 << ((sct_n * 2) + 1));
bogdanm 0:9b334a45a8ff 96
bogdanm 0:9b334a45a8ff 97 pwm->EVENT[(sct_n * 2) + 0].CTRL = (1 << 12) | ((sct_n * 2) + 0); // match event
bogdanm 0:9b334a45a8ff 98 pwm->EVENT[(sct_n * 2) + 0].STATE = 0xFFFFFFFF;
bogdanm 0:9b334a45a8ff 99 pwm->EVENT[(sct_n * 2) + 1].CTRL = (1 << 12) | ((sct_n * 2) + 1);
bogdanm 0:9b334a45a8ff 100 pwm->EVENT[(sct_n * 2) + 1].STATE = 0xFFFFFFFF;
bogdanm 0:9b334a45a8ff 101
bogdanm 0:9b334a45a8ff 102 // unhalt the counter:
bogdanm 0:9b334a45a8ff 103 // - clearing bit 2 of the CTRL register
bogdanm 0:9b334a45a8ff 104 pwm->CTRL &= ~(1 << 2);
bogdanm 0:9b334a45a8ff 105
bogdanm 0:9b334a45a8ff 106 // default to 20ms: standard for servos, and fine for e.g. brightness control
bogdanm 0:9b334a45a8ff 107 pwmout_period_ms(obj, 20);
bogdanm 0:9b334a45a8ff 108 pwmout_write (obj, 0);
bogdanm 0:9b334a45a8ff 109 }
bogdanm 0:9b334a45a8ff 110
bogdanm 0:9b334a45a8ff 111 void pwmout_free(pwmout_t* obj)
bogdanm 0:9b334a45a8ff 112 {
bogdanm 0:9b334a45a8ff 113 // Disable the SCT clock
bogdanm 0:9b334a45a8ff 114 LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 8);
bogdanm 0:9b334a45a8ff 115 sct_used &= ~(1 << obj->pwm_ch);
bogdanm 0:9b334a45a8ff 116 }
bogdanm 0:9b334a45a8ff 117
bogdanm 0:9b334a45a8ff 118 void pwmout_write(pwmout_t* obj, float value)
bogdanm 0:9b334a45a8ff 119 {
bogdanm 0:9b334a45a8ff 120 if (value < 0.0f) {
bogdanm 0:9b334a45a8ff 121 value = 0.0;
bogdanm 0:9b334a45a8ff 122 } else if (value > 1.0f) {
bogdanm 0:9b334a45a8ff 123 value = 1.0;
bogdanm 0:9b334a45a8ff 124 }
bogdanm 0:9b334a45a8ff 125 uint32_t t_on = (uint32_t)((float)(obj->pwm->MATCHREL[obj->pwm_ch * 2]) * value);
bogdanm 0:9b334a45a8ff 126 obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = t_on;
bogdanm 0:9b334a45a8ff 127 }
bogdanm 0:9b334a45a8ff 128
bogdanm 0:9b334a45a8ff 129 float pwmout_read(pwmout_t* obj)
bogdanm 0:9b334a45a8ff 130 {
bogdanm 0:9b334a45a8ff 131 uint32_t t_off = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0];
bogdanm 0:9b334a45a8ff 132 uint32_t t_on = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1];
bogdanm 0:9b334a45a8ff 133 float v = (float)t_on/(float)t_off;
bogdanm 0:9b334a45a8ff 134 return (v > 1.0f) ? (1.0f) : (v);
bogdanm 0:9b334a45a8ff 135 }
bogdanm 0:9b334a45a8ff 136
bogdanm 0:9b334a45a8ff 137 void pwmout_period(pwmout_t* obj, float seconds)
bogdanm 0:9b334a45a8ff 138 {
bogdanm 0:9b334a45a8ff 139 pwmout_period_us(obj, seconds * 1000000.0f);
bogdanm 0:9b334a45a8ff 140 }
bogdanm 0:9b334a45a8ff 141
bogdanm 0:9b334a45a8ff 142 void pwmout_period_ms(pwmout_t* obj, int ms)
bogdanm 0:9b334a45a8ff 143 {
bogdanm 0:9b334a45a8ff 144 pwmout_period_us(obj, ms * 1000);
bogdanm 0:9b334a45a8ff 145 }
bogdanm 0:9b334a45a8ff 146
bogdanm 0:9b334a45a8ff 147 // Set the PWM period, keeping the duty cycle the same.
bogdanm 0:9b334a45a8ff 148 void pwmout_period_us(pwmout_t* obj, int us)
bogdanm 0:9b334a45a8ff 149 {
bogdanm 0:9b334a45a8ff 150 uint32_t t_off = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0];
bogdanm 0:9b334a45a8ff 151 uint32_t t_on = obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1];
bogdanm 0:9b334a45a8ff 152 float v = (float)t_on/(float)t_off;
bogdanm 0:9b334a45a8ff 153 obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 0] = (uint32_t)us;
bogdanm 0:9b334a45a8ff 154 obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = (uint32_t)((float)us * (float)v);
bogdanm 0:9b334a45a8ff 155 }
bogdanm 0:9b334a45a8ff 156
bogdanm 0:9b334a45a8ff 157 void pwmout_pulsewidth(pwmout_t* obj, float seconds)
bogdanm 0:9b334a45a8ff 158 {
bogdanm 0:9b334a45a8ff 159 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
bogdanm 0:9b334a45a8ff 160 }
bogdanm 0:9b334a45a8ff 161
bogdanm 0:9b334a45a8ff 162 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms)
bogdanm 0:9b334a45a8ff 163 {
bogdanm 0:9b334a45a8ff 164 pwmout_pulsewidth_us(obj, ms * 1000);
bogdanm 0:9b334a45a8ff 165 }
bogdanm 0:9b334a45a8ff 166
bogdanm 0:9b334a45a8ff 167 void pwmout_pulsewidth_us(pwmout_t* obj, int us)
bogdanm 0:9b334a45a8ff 168 {
bogdanm 0:9b334a45a8ff 169 obj->pwm->MATCHREL[(obj->pwm_ch * 2) + 1] = (uint32_t)us;
bogdanm 0:9b334a45a8ff 170 }
bogdanm 0:9b334a45a8ff 171
bogdanm 0:9b334a45a8ff 172 #endif