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Fork of OmniWheels by Gustav Atmel

mbed-os/targets/TARGET_NXP/TARGET_LPC43XX/pwmout_api.c@1:9c5af431a1f1, 2018-05-01 (annotated)

Committer:
gustavatmel
Date:
Tue May 01 15:47:08 2018 +0000
Revision:
1:9c5af431a1f1
sdf

Who changed what in which revision?

UserRevisionLine numberNew contents of line
gustavatmel 1:9c5af431a1f1 1 /* mbed Microcontroller Library
gustavatmel 1:9c5af431a1f1 2 * Copyright (c) 2006-2013 ARM Limited
gustavatmel 1:9c5af431a1f1 3 *
gustavatmel 1:9c5af431a1f1 4 * Licensed under the Apache License, Version 2.0 (the "License");
gustavatmel 1:9c5af431a1f1 5 * you may not use this file except in compliance with the License.
gustavatmel 1:9c5af431a1f1 6 * You may obtain a copy of the License at
gustavatmel 1:9c5af431a1f1 7 *
gustavatmel 1:9c5af431a1f1 8 * http://www.apache.org/licenses/LICENSE-2.0
gustavatmel 1:9c5af431a1f1 9 *
gustavatmel 1:9c5af431a1f1 10 * Unless required by applicable law or agreed to in writing, software
gustavatmel 1:9c5af431a1f1 11 * distributed under the License is distributed on an "AS IS" BASIS,
gustavatmel 1:9c5af431a1f1 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
gustavatmel 1:9c5af431a1f1 13 * See the License for the specific language governing permissions and
gustavatmel 1:9c5af431a1f1 14 * limitations under the License.
gustavatmel 1:9c5af431a1f1 15 *
gustavatmel 1:9c5af431a1f1 16 * Ported to NXP LPC43XX by Micromint USA <support@micromint.com>
gustavatmel 1:9c5af431a1f1 17 */
gustavatmel 1:9c5af431a1f1 18 #include "mbed_assert.h"
gustavatmel 1:9c5af431a1f1 19 #include "pwmout_api.h"
gustavatmel 1:9c5af431a1f1 20 #include "cmsis.h"
gustavatmel 1:9c5af431a1f1 21 #include "pinmap.h"
gustavatmel 1:9c5af431a1f1 22 #include "mbed_error.h"
gustavatmel 1:9c5af431a1f1 23
gustavatmel 1:9c5af431a1f1 24 // PWM implementation for the LPC43xx using State Configurable Timer (SCT)
gustavatmel 1:9c5af431a1f1 25 // * PWM_0 to PWM_15 on mbed use CTOUT_0 to CTOUT_15 outputs on LPC43xx
gustavatmel 1:9c5af431a1f1 26 // * Event 0 is PWM period, events 1 to PWM_EVENT_MAX are PWM channels
gustavatmel 1:9c5af431a1f1 27 // * Default is unified 32-bit timer, but could be configured to use
gustavatmel 1:9c5af431a1f1 28 // a 16-bit timer so a timer is available for other SCT functions
gustavatmel 1:9c5af431a1f1 29
gustavatmel 1:9c5af431a1f1 30 // configuration options
gustavatmel 1:9c5af431a1f1 31 #define PWM_FREQ_BASE 1000000 // Base frequency 1 MHz = 1000000
gustavatmel 1:9c5af431a1f1 32 #ifndef PWM_MODE
gustavatmel 1:9c5af431a1f1 33 #define PWM_MODE 1 // 0 = 32-bit, 1 = 16-bit low, 2 = 16-bit high
gustavatmel 1:9c5af431a1f1 34 #endif
gustavatmel 1:9c5af431a1f1 35
gustavatmel 1:9c5af431a1f1 36 // macros
gustavatmel 1:9c5af431a1f1 37 #define PWM_SETCOUNT(x) (x - 1) // set count value
gustavatmel 1:9c5af431a1f1 38 #define PWM_GETCOUNT(x) (x + 1) // get count value
gustavatmel 1:9c5af431a1f1 39 #if (PWM_MODE == 0) // unified 32-bit counter, events 1 to 15
gustavatmel 1:9c5af431a1f1 40 #define PWM_EVENT_MAX (CONFIG_SCT_nEV - 1) // Max PWM channels
gustavatmel 1:9c5af431a1f1 41 #define PWM_CONFIG SCT_CONFIG_32BIT_COUNTER // default config
gustavatmel 1:9c5af431a1f1 42 #define PWM_CTRL &LPC_SCT->CTRL_U // control register
gustavatmel 1:9c5af431a1f1 43 #define PWM_HALT SCT_CTRL_HALT_L // halt counter
gustavatmel 1:9c5af431a1f1 44 #define PWM_CLEAR SCT_CTRL_CLRCTR_L // clock clear
gustavatmel 1:9c5af431a1f1 45 #define PWM_PRE(x) SCT_CTRL_PRE_L(x) // clock prescale
gustavatmel 1:9c5af431a1f1 46 #define PWM_EVT_MASK (1 << 12) // event control mask
gustavatmel 1:9c5af431a1f1 47 #define PWM_LIMIT &LPC_SCT->LIMIT_L // limit register
gustavatmel 1:9c5af431a1f1 48 #define PWM_MATCH(x) &LPC_SCT->MATCH[x].U // match register
gustavatmel 1:9c5af431a1f1 49 #define PWM_MR(x) &LPC_SCT->MATCHREL[x].U // 32-bit match reload register
gustavatmel 1:9c5af431a1f1 50 #elif (PWM_MODE == 1) // 16-bit low counter, events 1 to 7
gustavatmel 1:9c5af431a1f1 51 #define PWM_EVENT_MAX (CONFIG_SCT_nEV/2 - 1) // Max PWM channels
gustavatmel 1:9c5af431a1f1 52 #define PWM_CONFIG SCT_CONFIG_16BIT_COUNTER // default config
gustavatmel 1:9c5af431a1f1 53 #define PWM_CTRL &LPC_SCT->CTRL_L // control register
gustavatmel 1:9c5af431a1f1 54 #define PWM_HALT SCT_CTRL_HALT_L // halt counter
gustavatmel 1:9c5af431a1f1 55 #define PWM_CLEAR SCT_CTRL_CLRCTR_L // clock clear
gustavatmel 1:9c5af431a1f1 56 #define PWM_PRE(x) SCT_CTRL_PRE_L(x) // clock prescale
gustavatmel 1:9c5af431a1f1 57 #define PWM_EVT_MASK (1 << 12) // event control mask
gustavatmel 1:9c5af431a1f1 58 #define PWM_LIMIT &LPC_SCT->LIMIT_L // limit register
gustavatmel 1:9c5af431a1f1 59 #define PWM_MATCH(x) &LPC_SCT->MATCH[x].L // match register
gustavatmel 1:9c5af431a1f1 60 #define PWM_MR(x) &LPC_SCT->MATCHREL[x].L // 16-bit match reload register
gustavatmel 1:9c5af431a1f1 61 #elif (PWM_MODE == 2) // 16-bit high counter, events 1 to 7
gustavatmel 1:9c5af431a1f1 62 // [TODO] use events 8 to 15 on mode 2
gustavatmel 1:9c5af431a1f1 63 #define PWM_EVENT_MAX (CONFIG_SCT_nEV/2 - 1) // Max PWM channels
gustavatmel 1:9c5af431a1f1 64 #define PWM_CONFIG SCT_CONFIG_16BIT_COUNTER // default config
gustavatmel 1:9c5af431a1f1 65 #define PWM_CTRL &LPC_SCT->CTRL_H // control register
gustavatmel 1:9c5af431a1f1 66 #define PWM_HALT SCT_CTRL_HALT_L // halt counter
gustavatmel 1:9c5af431a1f1 67 #define PWM_CLEAR SCT_CTRL_CLRCTR_L // clock clear
gustavatmel 1:9c5af431a1f1 68 #define PWM_PRE(x) SCT_CTRL_PRE_L(x) // clock prescale
gustavatmel 1:9c5af431a1f1 69 #define PWM_EVT_MASK ((1 << 4) | (1 << 12)) // event control mask
gustavatmel 1:9c5af431a1f1 70 #define PWM_LIMIT &LPC_SCT->LIMIT_H // limit register
gustavatmel 1:9c5af431a1f1 71 #define PWM_MATCH(x) &LPC_SCT->MATCH[x].H // match register
gustavatmel 1:9c5af431a1f1 72 #define PWM_MR(x) &LPC_SCT->MATCHREL[x].H // 16-bit match reload register
gustavatmel 1:9c5af431a1f1 73 #else
gustavatmel 1:9c5af431a1f1 74 #error "PWM mode not implemented"
gustavatmel 1:9c5af431a1f1 75 #endif
gustavatmel 1:9c5af431a1f1 76 #define PWM_MR0 PWM_MR(0) // MR register 0 is for period
gustavatmel 1:9c5af431a1f1 77
gustavatmel 1:9c5af431a1f1 78 static uint8_t event = 0;
gustavatmel 1:9c5af431a1f1 79
gustavatmel 1:9c5af431a1f1 80 // PORT ID, PWM ID, Pin function
gustavatmel 1:9c5af431a1f1 81 static const PinMap PinMap_PWM[] = {
gustavatmel 1:9c5af431a1f1 82 {P1_1, PWM_7, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 83 {P1_2, PWM_6, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 84 {P1_3, PWM_8, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 85 {P1_4, PWM_9, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 86 {P1_5, PWM_10, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 87 {P1_7, PWM_13, (SCU_PINIO_FAST | 2)},
gustavatmel 1:9c5af431a1f1 88 {P1_8, PWM_12, (SCU_PINIO_FAST | 2)},
gustavatmel 1:9c5af431a1f1 89 {P1_9, PWM_11, (SCU_PINIO_FAST | 2)},
gustavatmel 1:9c5af431a1f1 90 {P1_10, PWM_14, (SCU_PINIO_FAST | 2)},
gustavatmel 1:9c5af431a1f1 91 {P1_11, PWM_15, (SCU_PINIO_FAST | 2)},
gustavatmel 1:9c5af431a1f1 92 {P2_7, PWM_1, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 93 {P2_8, PWM_0, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 94 {P2_9, PWM_3, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 95 {P2_10, PWM_2, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 96 {P2_11, PWM_5, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 97 {P2_12, PWM_4, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 98 {P4_1, PWM_1, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 99 {P4_2, PWM_0, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 100 {P4_3, PWM_3, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 101 {P4_4, PWM_2, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 102 {P4_5, PWM_5, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 103 {P4_6, PWM_4, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 104 {P6_5, PWM_6, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 105 {P6_12, PWM_7, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 106 {P7_0, PWM_14, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 107 {P7_1, PWM_15, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 108 {P7_4, PWM_13, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 109 {P7_5, PWM_12, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 110 {P7_6, PWM_11, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 111 {P7_7, PWM_8, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 112 {PA_4, PWM_9, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 113 {PB_0, PWM_10, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 114 {PB_1, PWM_6, (SCU_PINIO_FAST | 5)},
gustavatmel 1:9c5af431a1f1 115 {PB_2, PWM_7, (SCU_PINIO_FAST | 5)},
gustavatmel 1:9c5af431a1f1 116 {PB_3, PWM_8, (SCU_PINIO_FAST | 5)},
gustavatmel 1:9c5af431a1f1 117 {PD_0, PWM_15, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 118 {PD_2, PWM_7, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 119 {PD_3, PWM_6, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 120 {PD_4, PWM_8, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 121 {PD_5, PWM_9, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 122 {PD_6, PWM_10, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 123 {PD_9, PWM_13, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 124 {PD_11, PWM_14, (SCU_PINIO_FAST | 6)},
gustavatmel 1:9c5af431a1f1 125 {PD_12, PWM_10, (SCU_PINIO_FAST | 6)},
gustavatmel 1:9c5af431a1f1 126 {PD_13, PWM_13, (SCU_PINIO_FAST | 6)},
gustavatmel 1:9c5af431a1f1 127 {PD_14, PWM_11, (SCU_PINIO_FAST | 6)},
gustavatmel 1:9c5af431a1f1 128 {PD_15, PWM_8, (SCU_PINIO_FAST | 6)},
gustavatmel 1:9c5af431a1f1 129 {PD_16, PWM_12, (SCU_PINIO_FAST | 6)},
gustavatmel 1:9c5af431a1f1 130 {PE_5, PWM_3, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 131 {PE_6, PWM_2, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 132 {PE_7, PWM_5, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 133 {PE_8, PWM_4, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 134 {PE_11, PWM_12, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 135 {PE_12, PWM_11, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 136 {PE_13, PWM_14, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 137 {PE_15, PWM_0, (SCU_PINIO_FAST | 1)},
gustavatmel 1:9c5af431a1f1 138 {PF_9, PWM_1, (SCU_PINIO_FAST | 2)},
gustavatmel 1:9c5af431a1f1 139 {NC, NC, 0}
gustavatmel 1:9c5af431a1f1 140 };
gustavatmel 1:9c5af431a1f1 141
gustavatmel 1:9c5af431a1f1 142 static unsigned int pwm_clock_mhz;
gustavatmel 1:9c5af431a1f1 143
gustavatmel 1:9c5af431a1f1 144 static void _pwmout_dev_init() {
gustavatmel 1:9c5af431a1f1 145 uint32_t i;
gustavatmel 1:9c5af431a1f1 146
gustavatmel 1:9c5af431a1f1 147 // set SCT clock and config
gustavatmel 1:9c5af431a1f1 148 LPC_CCU1->CLKCCU[CLK_MX_SCT].CFG = (1 << 0); // enable SCT clock in CCU1
gustavatmel 1:9c5af431a1f1 149 LPC_SCT->CONFIG |= PWM_CONFIG; // set config options
gustavatmel 1:9c5af431a1f1 150 *PWM_CTRL |= PWM_HALT; // set HALT bit to stop counter
gustavatmel 1:9c5af431a1f1 151 // clear counter and set prescaler for desired freq
gustavatmel 1:9c5af431a1f1 152 *PWM_CTRL |= PWM_CLEAR | PWM_PRE(SystemCoreClock / PWM_FREQ_BASE - 1);
gustavatmel 1:9c5af431a1f1 153 pwm_clock_mhz = PWM_FREQ_BASE / 1000000;
gustavatmel 1:9c5af431a1f1 154
gustavatmel 1:9c5af431a1f1 155 // configure SCT events
gustavatmel 1:9c5af431a1f1 156 for (i = 0; i < PWM_EVENT_MAX; i++) {
gustavatmel 1:9c5af431a1f1 157 *PWM_MATCH(i) = 0; // match register
gustavatmel 1:9c5af431a1f1 158 *PWM_MR(i) = 0; // match reload register
gustavatmel 1:9c5af431a1f1 159 LPC_SCT->EVENT[i].STATE = 0xFFFFFFFF; // event happens in all states
gustavatmel 1:9c5af431a1f1 160 LPC_SCT->EVENT[i].CTRL = (i << 0) | PWM_EVT_MASK; // match condition only
gustavatmel 1:9c5af431a1f1 161 }
gustavatmel 1:9c5af431a1f1 162 *PWM_LIMIT = (1 << 0) ; // set event 0 as limit
gustavatmel 1:9c5af431a1f1 163 // initialize period to 20ms: standard for servos, and fine for e.g. brightness control
gustavatmel 1:9c5af431a1f1 164 *PWM_MR0 = PWM_SETCOUNT((uint32_t)(((20 * PWM_FREQ_BASE) / 1000000) * 1000));
gustavatmel 1:9c5af431a1f1 165
gustavatmel 1:9c5af431a1f1 166 // initialize SCT outputs
gustavatmel 1:9c5af431a1f1 167 for (i = 0; i < CONFIG_SCT_nOU; i++) {
gustavatmel 1:9c5af431a1f1 168 LPC_SCT->OUT[i].SET = 0; // defer set event until pulsewidth defined
gustavatmel 1:9c5af431a1f1 169 LPC_SCT->OUT[i].CLR = (1 << 0); // event 0 clears PWM pin
gustavatmel 1:9c5af431a1f1 170 }
gustavatmel 1:9c5af431a1f1 171 LPC_SCT->OUTPUT = 0; // default outputs to clear
gustavatmel 1:9c5af431a1f1 172
gustavatmel 1:9c5af431a1f1 173 *PWM_CTRL &= ~PWM_HALT; // clear HALT bit to start counter
gustavatmel 1:9c5af431a1f1 174 }
gustavatmel 1:9c5af431a1f1 175
gustavatmel 1:9c5af431a1f1 176 void pwmout_init(pwmout_t* obj, PinName pin) {
gustavatmel 1:9c5af431a1f1 177 // determine the channel
gustavatmel 1:9c5af431a1f1 178 PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
gustavatmel 1:9c5af431a1f1 179 MBED_ASSERT((pwm != (PWMName)NC) && (event < PWM_EVENT_MAX));
gustavatmel 1:9c5af431a1f1 180
gustavatmel 1:9c5af431a1f1 181 // init SCT clock and outputs on first PWM init
gustavatmel 1:9c5af431a1f1 182 if (event == 0) {
gustavatmel 1:9c5af431a1f1 183 _pwmout_dev_init();
gustavatmel 1:9c5af431a1f1 184 }
gustavatmel 1:9c5af431a1f1 185 // init PWM object
gustavatmel 1:9c5af431a1f1 186 event++;
gustavatmel 1:9c5af431a1f1 187 obj->pwm = pwm; // pwm output
gustavatmel 1:9c5af431a1f1 188 obj->mr = event; // index of match reload register
gustavatmel 1:9c5af431a1f1 189
gustavatmel 1:9c5af431a1f1 190 // initial duty cycle is 0
gustavatmel 1:9c5af431a1f1 191 pwmout_write(obj, 0);
gustavatmel 1:9c5af431a1f1 192
gustavatmel 1:9c5af431a1f1 193 // Wire pinout
gustavatmel 1:9c5af431a1f1 194 pinmap_pinout(pin, PinMap_PWM);
gustavatmel 1:9c5af431a1f1 195 }
gustavatmel 1:9c5af431a1f1 196
gustavatmel 1:9c5af431a1f1 197 void pwmout_free(pwmout_t* obj) {
gustavatmel 1:9c5af431a1f1 198 // [TODO]
gustavatmel 1:9c5af431a1f1 199 }
gustavatmel 1:9c5af431a1f1 200
gustavatmel 1:9c5af431a1f1 201 void pwmout_write(pwmout_t* obj, float value) {
gustavatmel 1:9c5af431a1f1 202 if (value < 0.0f) {
gustavatmel 1:9c5af431a1f1 203 value = 0.0;
gustavatmel 1:9c5af431a1f1 204 } else if (value > 1.0f) {
gustavatmel 1:9c5af431a1f1 205 value = 1.0;
gustavatmel 1:9c5af431a1f1 206 }
gustavatmel 1:9c5af431a1f1 207
gustavatmel 1:9c5af431a1f1 208 // set new pulse width
gustavatmel 1:9c5af431a1f1 209 uint32_t us = (uint32_t)((float)PWM_GETCOUNT(*PWM_MR0) * value) * pwm_clock_mhz;
gustavatmel 1:9c5af431a1f1 210 pwmout_pulsewidth_us(obj, us);
gustavatmel 1:9c5af431a1f1 211 }
gustavatmel 1:9c5af431a1f1 212
gustavatmel 1:9c5af431a1f1 213 float pwmout_read(pwmout_t* obj) {
gustavatmel 1:9c5af431a1f1 214 float v = (float)PWM_GETCOUNT(*PWM_MR(obj->mr)) / (float)PWM_GETCOUNT(*PWM_MR0);
gustavatmel 1:9c5af431a1f1 215 return (v > 1.0f) ? (1.0f) : (v);
gustavatmel 1:9c5af431a1f1 216 }
gustavatmel 1:9c5af431a1f1 217
gustavatmel 1:9c5af431a1f1 218 void pwmout_period(pwmout_t* obj, float seconds) {
gustavatmel 1:9c5af431a1f1 219 pwmout_period_us(obj, seconds * 1000000.0f);
gustavatmel 1:9c5af431a1f1 220 }
gustavatmel 1:9c5af431a1f1 221
gustavatmel 1:9c5af431a1f1 222 void pwmout_period_ms(pwmout_t* obj, int ms) {
gustavatmel 1:9c5af431a1f1 223 pwmout_period_us(obj, ms * 1000);
gustavatmel 1:9c5af431a1f1 224 }
gustavatmel 1:9c5af431a1f1 225
gustavatmel 1:9c5af431a1f1 226 // Set the PWM period, keeping the duty cycle the same.
gustavatmel 1:9c5af431a1f1 227 void pwmout_period_us(pwmout_t* obj, int us) {
gustavatmel 1:9c5af431a1f1 228 // calculate number of ticks
gustavatmel 1:9c5af431a1f1 229 uint32_t ticks = pwm_clock_mhz * us;
gustavatmel 1:9c5af431a1f1 230 uint32_t old_ticks = PWM_GETCOUNT(*PWM_MR0);
gustavatmel 1:9c5af431a1f1 231 uint32_t i, v;
gustavatmel 1:9c5af431a1f1 232
gustavatmel 1:9c5af431a1f1 233 // set new period
gustavatmel 1:9c5af431a1f1 234 *PWM_MR0 = PWM_SETCOUNT(ticks);
gustavatmel 1:9c5af431a1f1 235
gustavatmel 1:9c5af431a1f1 236 // Scale pulse widths to preserve the duty ratio
gustavatmel 1:9c5af431a1f1 237 for (i = 1; i < PWM_EVENT_MAX; i++) {
gustavatmel 1:9c5af431a1f1 238 v = PWM_GETCOUNT(*PWM_MR(i));
gustavatmel 1:9c5af431a1f1 239 if (v > 1) {
gustavatmel 1:9c5af431a1f1 240 v = (v * ticks) / old_ticks;
gustavatmel 1:9c5af431a1f1 241 *PWM_MR(i) = PWM_SETCOUNT(v);
gustavatmel 1:9c5af431a1f1 242 }
gustavatmel 1:9c5af431a1f1 243 }
gustavatmel 1:9c5af431a1f1 244 }
gustavatmel 1:9c5af431a1f1 245
gustavatmel 1:9c5af431a1f1 246 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
gustavatmel 1:9c5af431a1f1 247 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
gustavatmel 1:9c5af431a1f1 248 }
gustavatmel 1:9c5af431a1f1 249
gustavatmel 1:9c5af431a1f1 250 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
gustavatmel 1:9c5af431a1f1 251 pwmout_pulsewidth_us(obj, ms * 1000);
gustavatmel 1:9c5af431a1f1 252 }
gustavatmel 1:9c5af431a1f1 253
gustavatmel 1:9c5af431a1f1 254 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
gustavatmel 1:9c5af431a1f1 255 // calculate number of ticks
gustavatmel 1:9c5af431a1f1 256 uint32_t v = pwm_clock_mhz * us;
gustavatmel 1:9c5af431a1f1 257 uint32_t i = obj->pwm;
gustavatmel 1:9c5af431a1f1 258 //MBED_ASSERT(PWM_GETCOUNT(*PWM_MR0) >= v);
gustavatmel 1:9c5af431a1f1 259
gustavatmel 1:9c5af431a1f1 260 if (v > 0) {
gustavatmel 1:9c5af431a1f1 261 // set new match register value and enable SCT output
gustavatmel 1:9c5af431a1f1 262 *PWM_MR(obj->mr) = PWM_SETCOUNT(v);
gustavatmel 1:9c5af431a1f1 263 LPC_SCT->OUT[i].SET = (1 << 0); // event 0 sets PWM pin
gustavatmel 1:9c5af431a1f1 264 LPC_SCT->OUT[i].CLR = (1 << obj->mr); // match event clears PWM pin
gustavatmel 1:9c5af431a1f1 265 } else {
gustavatmel 1:9c5af431a1f1 266 // set match to zero and clear SCT output
gustavatmel 1:9c5af431a1f1 267 *PWM_MR(obj->mr) = 0;
gustavatmel 1:9c5af431a1f1 268 LPC_SCT->OUT[i].SET = 0; // no set event if no pulsewidth defined
gustavatmel 1:9c5af431a1f1 269 LPC_SCT->OUT[i].CLR = (1 << 0); // event 0 clears PWM pin
gustavatmel 1:9c5af431a1f1 270 }
gustavatmel 1:9c5af431a1f1 271 }