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This library was superseded by mbed-dev - https://os.mbed.com/users/mbed_official/code/mbed-dev/.

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Last commit 20 Feb 2019 by mbed official

targets/hal/TARGET_NXP/TARGET_LPC2460/pwmout_api.c@621:9c82b0f79f3d, 2015-09-11 (annotated)

Committer:
mbed_official
Date:
Fri Sep 11 09:30:09 2015 +0100
Revision:
621:9c82b0f79f3d
Parent:
554:edd95c0879f8 
Synchronized with git revision 6c1d63e069ab9bd86de92e8296ca783681257538



Full URL: https://github.com/mbedmicro/mbed/commit/6c1d63e069ab9bd86de92e8296ca783681257538/



ignore target files not supported by the yotta module

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 554:edd95c0879f8 1 /* mbed Microcontroller Library
mbed_official 554:edd95c0879f8 2 * Copyright (c) 2006-2015 ARM Limited
mbed_official 554:edd95c0879f8 3 *
mbed_official 554:edd95c0879f8 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 554:edd95c0879f8 5 * you may not use this file except in compliance with the License.
mbed_official 554:edd95c0879f8 6 * You may obtain a copy of the License at
mbed_official 554:edd95c0879f8 7 *
mbed_official 554:edd95c0879f8 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 554:edd95c0879f8 9 *
mbed_official 554:edd95c0879f8 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 554:edd95c0879f8 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 554:edd95c0879f8 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 554:edd95c0879f8 13 * See the License for the specific language governing permissions and
mbed_official 554:edd95c0879f8 14 * limitations under the License.
mbed_official 554:edd95c0879f8 15 */
mbed_official 554:edd95c0879f8 16 #include "mbed_assert.h"
mbed_official 554:edd95c0879f8 17 #include "pwmout_api.h"
mbed_official 554:edd95c0879f8 18 #include "cmsis.h"
mbed_official 554:edd95c0879f8 19 #include "pinmap.h"
mbed_official 554:edd95c0879f8 20
mbed_official 554:edd95c0879f8 21 #define TCR_CNT_EN 0x00000001
mbed_official 554:edd95c0879f8 22 #define TCR_RESET 0x00000002
mbed_official 554:edd95c0879f8 23
mbed_official 554:edd95c0879f8 24 // PORT ID, PWM ID, Pin function
mbed_official 554:edd95c0879f8 25 static const PinMap PinMap_PWM[] = {
mbed_official 554:edd95c0879f8 26 {P1_18, PWM_1, 2},
mbed_official 554:edd95c0879f8 27 {P1_20, PWM_2, 2},
mbed_official 554:edd95c0879f8 28 {P1_21, PWM_3, 2},
mbed_official 554:edd95c0879f8 29 {P1_23, PWM_4, 2},
mbed_official 554:edd95c0879f8 30 {P1_24, PWM_5, 2},
mbed_official 554:edd95c0879f8 31 {P1_26, PWM_6, 2},
mbed_official 554:edd95c0879f8 32 {P2_0 , PWM_1, 1},
mbed_official 554:edd95c0879f8 33 {P2_1 , PWM_2, 1},
mbed_official 554:edd95c0879f8 34 {P2_2 , PWM_3, 1},
mbed_official 554:edd95c0879f8 35 {P2_3 , PWM_4, 1},
mbed_official 554:edd95c0879f8 36 {P2_4 , PWM_5, 1},
mbed_official 554:edd95c0879f8 37 {P2_5 , PWM_6, 1},
mbed_official 554:edd95c0879f8 38 {P3_24, PWM_1, 3},
mbed_official 554:edd95c0879f8 39 {P3_25, PWM_2, 3},
mbed_official 554:edd95c0879f8 40 {P3_26, PWM_3, 3},
mbed_official 554:edd95c0879f8 41 {P3_27, PWM_4, 3},
mbed_official 554:edd95c0879f8 42 {P3_28, PWM_5, 3},
mbed_official 554:edd95c0879f8 43 {P3_29, PWM_6, 3},
mbed_official 554:edd95c0879f8 44 {NC, NC, 0}
mbed_official 554:edd95c0879f8 45 };
mbed_official 554:edd95c0879f8 46
mbed_official 554:edd95c0879f8 47 __IO uint32_t *PWM_MATCH[] = {
mbed_official 554:edd95c0879f8 48 &(LPC_PWM1->MR0),
mbed_official 554:edd95c0879f8 49 &(LPC_PWM1->MR1),
mbed_official 554:edd95c0879f8 50 &(LPC_PWM1->MR2),
mbed_official 554:edd95c0879f8 51 &(LPC_PWM1->MR3),
mbed_official 554:edd95c0879f8 52 &(LPC_PWM1->MR4),
mbed_official 554:edd95c0879f8 53 &(LPC_PWM1->MR5),
mbed_official 554:edd95c0879f8 54 &(LPC_PWM1->MR6)
mbed_official 554:edd95c0879f8 55 };
mbed_official 554:edd95c0879f8 56
mbed_official 554:edd95c0879f8 57 #define TCR_PWM_EN 0x00000008
mbed_official 554:edd95c0879f8 58
mbed_official 554:edd95c0879f8 59 static unsigned int pwm_clock_mhz;
mbed_official 554:edd95c0879f8 60
mbed_official 554:edd95c0879f8 61 void pwmout_init(pwmout_t* obj, PinName pin) {
mbed_official 554:edd95c0879f8 62 // determine the channel
mbed_official 554:edd95c0879f8 63 PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
mbed_official 554:edd95c0879f8 64 MBED_ASSERT(pwm != (PWMName)NC);
mbed_official 554:edd95c0879f8 65
mbed_official 554:edd95c0879f8 66 obj->pwm = pwm;
mbed_official 554:edd95c0879f8 67 obj->MR = PWM_MATCH[pwm];
mbed_official 554:edd95c0879f8 68
mbed_official 554:edd95c0879f8 69 // ensure the power is on
mbed_official 554:edd95c0879f8 70 LPC_SC->PCONP |= 1 << 6;
mbed_official 554:edd95c0879f8 71
mbed_official 554:edd95c0879f8 72 // ensure clock to /4
mbed_official 554:edd95c0879f8 73 LPC_SC->PCLKSEL0 &= ~(0x3 << 12); // pclk = /4
mbed_official 554:edd95c0879f8 74 LPC_PWM1->PR = 0; // no pre-scale
mbed_official 554:edd95c0879f8 75
mbed_official 554:edd95c0879f8 76 // ensure single PWM mode
mbed_official 554:edd95c0879f8 77 LPC_PWM1->MCR = 1 << 1; // reset TC on match 0
mbed_official 554:edd95c0879f8 78
mbed_official 554:edd95c0879f8 79 // enable the specific PWM output
mbed_official 554:edd95c0879f8 80 LPC_PWM1->PCR |= 1 << (8 + pwm);
mbed_official 554:edd95c0879f8 81
mbed_official 554:edd95c0879f8 82 pwm_clock_mhz = SystemCoreClock / 4000000;
mbed_official 554:edd95c0879f8 83
mbed_official 554:edd95c0879f8 84 // default to 20ms: standard for servos, and fine for e.g. brightness control
mbed_official 554:edd95c0879f8 85 pwmout_period_ms(obj, 20);
mbed_official 554:edd95c0879f8 86 pwmout_write (obj, 0);
mbed_official 554:edd95c0879f8 87
mbed_official 554:edd95c0879f8 88 // Wire pinout
mbed_official 554:edd95c0879f8 89 pinmap_pinout(pin, PinMap_PWM);
mbed_official 554:edd95c0879f8 90 }
mbed_official 554:edd95c0879f8 91
mbed_official 554:edd95c0879f8 92 void pwmout_free(pwmout_t* obj) {
mbed_official 554:edd95c0879f8 93 // [TODO]
mbed_official 554:edd95c0879f8 94 }
mbed_official 554:edd95c0879f8 95
mbed_official 554:edd95c0879f8 96 void pwmout_write(pwmout_t* obj, float value) {
mbed_official 554:edd95c0879f8 97 if (value < 0.0f) {
mbed_official 554:edd95c0879f8 98 value = 0.0;
mbed_official 554:edd95c0879f8 99 } else if (value > 1.0f) {
mbed_official 554:edd95c0879f8 100 value = 1.0;
mbed_official 554:edd95c0879f8 101 }
mbed_official 554:edd95c0879f8 102
mbed_official 554:edd95c0879f8 103 // set channel match to percentage
mbed_official 554:edd95c0879f8 104 uint32_t v = (uint32_t)((float)(LPC_PWM1->MR0) * value);
mbed_official 554:edd95c0879f8 105
mbed_official 554:edd95c0879f8 106 // workaround for PWM1[1] - Never make it equal MR0, else we get 1 cycle dropout
mbed_official 554:edd95c0879f8 107 if (v == LPC_PWM1->MR0) {
mbed_official 554:edd95c0879f8 108 v++;
mbed_official 554:edd95c0879f8 109 }
mbed_official 554:edd95c0879f8 110
mbed_official 554:edd95c0879f8 111 *obj->MR = v;
mbed_official 554:edd95c0879f8 112
mbed_official 554:edd95c0879f8 113 // accept on next period start
mbed_official 554:edd95c0879f8 114 LPC_PWM1->LER |= 1 << obj->pwm;
mbed_official 554:edd95c0879f8 115 }
mbed_official 554:edd95c0879f8 116
mbed_official 554:edd95c0879f8 117 float pwmout_read(pwmout_t* obj) {
mbed_official 554:edd95c0879f8 118 float v = (float)(*obj->MR) / (float)(LPC_PWM1->MR0);
mbed_official 554:edd95c0879f8 119 return (v > 1.0f) ? (1.0f) : (v);
mbed_official 554:edd95c0879f8 120 }
mbed_official 554:edd95c0879f8 121
mbed_official 554:edd95c0879f8 122 void pwmout_period(pwmout_t* obj, float seconds) {
mbed_official 554:edd95c0879f8 123 pwmout_period_us(obj, seconds * 1000000.0f);
mbed_official 554:edd95c0879f8 124 }
mbed_official 554:edd95c0879f8 125
mbed_official 554:edd95c0879f8 126 void pwmout_period_ms(pwmout_t* obj, int ms) {
mbed_official 554:edd95c0879f8 127 pwmout_period_us(obj, ms * 1000);
mbed_official 554:edd95c0879f8 128 }
mbed_official 554:edd95c0879f8 129
mbed_official 554:edd95c0879f8 130 // Set the PWM period, keeping the duty cycle the same.
mbed_official 554:edd95c0879f8 131 void pwmout_period_us(pwmout_t* obj, int us) {
mbed_official 554:edd95c0879f8 132 // calculate number of ticks
mbed_official 554:edd95c0879f8 133 uint32_t ticks = pwm_clock_mhz * us;
mbed_official 554:edd95c0879f8 134
mbed_official 554:edd95c0879f8 135 // set reset
mbed_official 554:edd95c0879f8 136 LPC_PWM1->TCR = TCR_RESET;
mbed_official 554:edd95c0879f8 137
mbed_official 554:edd95c0879f8 138 // set the global match register
mbed_official 554:edd95c0879f8 139 LPC_PWM1->MR0 = ticks;
mbed_official 554:edd95c0879f8 140
mbed_official 554:edd95c0879f8 141 // Scale the pulse width to preserve the duty ratio
mbed_official 554:edd95c0879f8 142 if (LPC_PWM1->MR0 > 0) {
mbed_official 554:edd95c0879f8 143 *obj->MR = (*obj->MR * ticks) / LPC_PWM1->MR0;
mbed_official 554:edd95c0879f8 144 }
mbed_official 554:edd95c0879f8 145
mbed_official 554:edd95c0879f8 146 // set the channel latch to update value at next period start
mbed_official 554:edd95c0879f8 147 LPC_PWM1->LER |= 1 << 0;
mbed_official 554:edd95c0879f8 148
mbed_official 554:edd95c0879f8 149 // enable counter and pwm, clear reset
mbed_official 554:edd95c0879f8 150 LPC_PWM1->TCR = TCR_CNT_EN | TCR_PWM_EN;
mbed_official 554:edd95c0879f8 151 }
mbed_official 554:edd95c0879f8 152
mbed_official 554:edd95c0879f8 153 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
mbed_official 554:edd95c0879f8 154 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
mbed_official 554:edd95c0879f8 155 }
mbed_official 554:edd95c0879f8 156
mbed_official 554:edd95c0879f8 157 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
mbed_official 554:edd95c0879f8 158 pwmout_pulsewidth_us(obj, ms * 1000);
mbed_official 554:edd95c0879f8 159 }
mbed_official 554:edd95c0879f8 160
mbed_official 554:edd95c0879f8 161 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
mbed_official 554:edd95c0879f8 162 // calculate number of ticks
mbed_official 554:edd95c0879f8 163 uint32_t v = pwm_clock_mhz * us;
mbed_official 554:edd95c0879f8 164
mbed_official 554:edd95c0879f8 165 // workaround for PWM1[1] - Never make it equal MR0, else we get 1 cycle dropout
mbed_official 554:edd95c0879f8 166 if (v == LPC_PWM1->MR0) {
mbed_official 554:edd95c0879f8 167 v++;
mbed_official 554:edd95c0879f8 168 }
mbed_official 554:edd95c0879f8 169
mbed_official 554:edd95c0879f8 170 // set the match register value
mbed_official 554:edd95c0879f8 171 *obj->MR = v;
mbed_official 554:edd95c0879f8 172
mbed_official 554:edd95c0879f8 173 // set the channel latch to update value at next period start
mbed_official 554:edd95c0879f8 174 LPC_PWM1->LER |= 1 << obj->pwm;
mbed_official 554:edd95c0879f8 175 }