david dicarlo / mbed-src-FLL48

mbed library sources: Modified to operate FRDM-KL25Z at 48MHz from internal 32kHz oscillator (nothing else changed).

Fork of mbed-src by mbed official

The only file that changed is: mbed-src-FLL48/targets/cmsis/TARGET_Freescale/TARGET_KL25Z/system_MKL25Z4.h

targets/hal/TARGET_NXP/TARGET_LPC11XX/pwmout_api.c@20:4263a77256ae, 2013-09-10 (annotated)

Committer:
bogdanm
Date:
Tue Sep 10 15:14:19 2013 +0300
Revision:
20:4263a77256ae
Parent:
19:398f4c622e1b 
Sync with git revision 171dda705c947bf910926a0b73d6a4797802554d

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 19:398f4c622e1b 1 /* mbed Microcontroller Library
bogdanm 19:398f4c622e1b 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 19:398f4c622e1b 3 *
bogdanm 19:398f4c622e1b 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 19:398f4c622e1b 5 * you may not use this file except in compliance with the License.
bogdanm 19:398f4c622e1b 6 * You may obtain a copy of the License at
bogdanm 19:398f4c622e1b 7 *
bogdanm 19:398f4c622e1b 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 19:398f4c622e1b 9 *
bogdanm 19:398f4c622e1b 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 19:398f4c622e1b 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 19:398f4c622e1b 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 19:398f4c622e1b 13 * See the License for the specific language governing permissions and
bogdanm 19:398f4c622e1b 14 * limitations under the License.
bogdanm 19:398f4c622e1b 15 */
bogdanm 19:398f4c622e1b 16 #include "pwmout_api.h"
bogdanm 19:398f4c622e1b 17 #include "cmsis.h"
bogdanm 19:398f4c622e1b 18 #include "pinmap.h"
bogdanm 19:398f4c622e1b 19 #include "error.h"
bogdanm 19:398f4c622e1b 20
bogdanm 19:398f4c622e1b 21 #define TCR_CNT_EN 0x00000001
bogdanm 19:398f4c622e1b 22 #define TCR_RESET 0x00000002
bogdanm 19:398f4c622e1b 23
bogdanm 19:398f4c622e1b 24 /* To have a PWM where we can change both the period and the duty cycle,
bogdanm 19:398f4c622e1b 25 * we need an entire timer. With the following conventions:
bogdanm 19:398f4c622e1b 26 * * MR3 is used for the PWM period
bogdanm 19:398f4c622e1b 27 * * MR0, MR1, MR2 are used for the duty cycle
bogdanm 19:398f4c622e1b 28 */
bogdanm 19:398f4c622e1b 29 static const PinMap PinMap_PWM[] = {
bogdanm 19:398f4c622e1b 30 /* CT16B0 */
bogdanm 19:398f4c622e1b 31 {P0_8 , PWM_1, 0x02}, /* MR0 */
bogdanm 19:398f4c622e1b 32 {P0_9 , PWM_2, 0x02}, /* MR1 */
bogdanm 19:398f4c622e1b 33
bogdanm 19:398f4c622e1b 34 /* CT16B1 */
bogdanm 20:4263a77256ae 35 {P1_9 , PWM_3, 0x01}, /* MR0 */
bogdanm 20:4263a77256ae 36 {P1_10, PWM_4, 0x02}, /* MR1 */
bogdanm 19:398f4c622e1b 37
bogdanm 19:398f4c622e1b 38 /* CT32B0 */
bogdanm 20:4263a77256ae 39 {P0_1 , PWM_5, 0x02}, /* MR2 */
bogdanm 19:398f4c622e1b 40
bogdanm 19:398f4c622e1b 41 {NC , NC ,0x00}
bogdanm 19:398f4c622e1b 42 };
bogdanm 19:398f4c622e1b 43
bogdanm 19:398f4c622e1b 44 typedef struct {
bogdanm 19:398f4c622e1b 45 uint8_t timer;
bogdanm 19:398f4c622e1b 46 uint8_t mr;
bogdanm 19:398f4c622e1b 47 } timer_mr;
bogdanm 19:398f4c622e1b 48
bogdanm 20:4263a77256ae 49 static timer_mr pwm_timer_map[5] = {
bogdanm 19:398f4c622e1b 50 {0, 0}, /* CT16B0, MR0 */
bogdanm 19:398f4c622e1b 51 {0, 1}, /* CT16B0, MR1 */
bogdanm 19:398f4c622e1b 52
bogdanm 19:398f4c622e1b 53 {1, 0}, /* CT16B1, MR0 */
bogdanm 19:398f4c622e1b 54 {1, 1}, /* CT16B1, MR1 */
bogdanm 19:398f4c622e1b 55
bogdanm 19:398f4c622e1b 56 {2, 2}, /* CT32B0, MR2 */
bogdanm 19:398f4c622e1b 57 };
bogdanm 19:398f4c622e1b 58
bogdanm 20:4263a77256ae 59 static LPC_TMR_TypeDef *Timers[3] = {
bogdanm 19:398f4c622e1b 60 LPC_TMR16B0, LPC_TMR16B1,
bogdanm 20:4263a77256ae 61 LPC_TMR32B0
bogdanm 19:398f4c622e1b 62 };
bogdanm 19:398f4c622e1b 63
bogdanm 19:398f4c622e1b 64 void pwmout_init(pwmout_t* obj, PinName pin) {
bogdanm 19:398f4c622e1b 65 // determine the channel
bogdanm 19:398f4c622e1b 66 PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
bogdanm 19:398f4c622e1b 67 if (pwm == (uint32_t)NC)
bogdanm 19:398f4c622e1b 68 error("PwmOut pin mapping failed");
bogdanm 19:398f4c622e1b 69
bogdanm 19:398f4c622e1b 70 obj->pwm = pwm;
bogdanm 19:398f4c622e1b 71
bogdanm 19:398f4c622e1b 72 // Timer registers
bogdanm 19:398f4c622e1b 73 timer_mr tid = pwm_timer_map[pwm];
bogdanm 19:398f4c622e1b 74 LPC_TMR_TypeDef *timer = Timers[tid.timer];
bogdanm 19:398f4c622e1b 75
bogdanm 19:398f4c622e1b 76 // Disable timer
bogdanm 19:398f4c622e1b 77 timer->TCR = 0;
bogdanm 19:398f4c622e1b 78
bogdanm 19:398f4c622e1b 79 // Power the correspondent timer
bogdanm 19:398f4c622e1b 80 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << (tid.timer + 7);
bogdanm 19:398f4c622e1b 81
bogdanm 19:398f4c622e1b 82 /* Enable PWM function */
bogdanm 19:398f4c622e1b 83 timer->PWMC = (1 << 3)|(1 << 2)|(1 << 1)|(1 << 0);
bogdanm 19:398f4c622e1b 84
bogdanm 19:398f4c622e1b 85 /* Reset Functionality on MR3 controlling the PWM period */
bogdanm 19:398f4c622e1b 86 timer->MCR = 1 << 10;
bogdanm 19:398f4c622e1b 87
bogdanm 20:4263a77256ae 88 if (timer == LPC_TMR16B0 || timer == LPC_TMR16B1) {
bogdanm 20:4263a77256ae 89 /* Set 16-bit timer prescaler to avoid timer expire for default 20ms */
bogdanm 20:4263a77256ae 90 /* This can be also modified by user application, but the prescaler value */
bogdanm 20:4263a77256ae 91 /* might be trade-off to timer accuracy */
bogdanm 20:4263a77256ae 92 timer->PR = 30;
bogdanm 20:4263a77256ae 93 }
bogdanm 20:4263a77256ae 94
bogdanm 19:398f4c622e1b 95 // default to 20ms: standard for servos, and fine for e.g. brightness control
bogdanm 19:398f4c622e1b 96 pwmout_period_ms(obj, 20);
bogdanm 19:398f4c622e1b 97 pwmout_write (obj, 0);
bogdanm 19:398f4c622e1b 98
bogdanm 19:398f4c622e1b 99 // Wire pinout
bogdanm 19:398f4c622e1b 100 pinmap_pinout(pin, PinMap_PWM);
bogdanm 19:398f4c622e1b 101 }
bogdanm 19:398f4c622e1b 102
bogdanm 19:398f4c622e1b 103 void pwmout_free(pwmout_t* obj) {
bogdanm 19:398f4c622e1b 104 // [TODO]
bogdanm 19:398f4c622e1b 105 }
bogdanm 19:398f4c622e1b 106
bogdanm 19:398f4c622e1b 107 void pwmout_write(pwmout_t* obj, float value) {
bogdanm 19:398f4c622e1b 108 if (value < 0.0f) {
bogdanm 19:398f4c622e1b 109 value = 0.0;
bogdanm 19:398f4c622e1b 110 } else if (value > 1.0f) {
bogdanm 19:398f4c622e1b 111 value = 1.0;
bogdanm 19:398f4c622e1b 112 }
bogdanm 19:398f4c622e1b 113
bogdanm 19:398f4c622e1b 114 timer_mr tid = pwm_timer_map[obj->pwm];
bogdanm 19:398f4c622e1b 115 LPC_TMR_TypeDef *timer = Timers[tid.timer];
bogdanm 19:398f4c622e1b 116 uint32_t t_off = timer->MR3 - (uint32_t)((float)(timer->MR3) * value);
bogdanm 19:398f4c622e1b 117
bogdanm 19:398f4c622e1b 118 timer->TCR = TCR_RESET;
bogdanm 19:398f4c622e1b 119 timer->MR[tid.mr] = t_off;
bogdanm 19:398f4c622e1b 120 timer->TCR = TCR_CNT_EN;
bogdanm 19:398f4c622e1b 121 }
bogdanm 19:398f4c622e1b 122
bogdanm 19:398f4c622e1b 123 float pwmout_read(pwmout_t* obj) {
bogdanm 19:398f4c622e1b 124 timer_mr tid = pwm_timer_map[obj->pwm];
bogdanm 19:398f4c622e1b 125 LPC_TMR_TypeDef *timer = Timers[tid.timer];
bogdanm 19:398f4c622e1b 126
bogdanm 19:398f4c622e1b 127 float v = (float)(timer->MR3 - timer->MR[tid.mr]) / (float)(timer->MR3);
bogdanm 19:398f4c622e1b 128 return (v > 1.0f) ? (1.0f) : (v);
bogdanm 19:398f4c622e1b 129 }
bogdanm 19:398f4c622e1b 130
bogdanm 19:398f4c622e1b 131 void pwmout_period(pwmout_t* obj, float seconds) {
bogdanm 19:398f4c622e1b 132 pwmout_period_us(obj, seconds * 1000000.0f);
bogdanm 19:398f4c622e1b 133 }
bogdanm 19:398f4c622e1b 134
bogdanm 19:398f4c622e1b 135 void pwmout_period_ms(pwmout_t* obj, int ms) {
bogdanm 19:398f4c622e1b 136 pwmout_period_us(obj, ms * 1000);
bogdanm 19:398f4c622e1b 137 }
bogdanm 19:398f4c622e1b 138
bogdanm 19:398f4c622e1b 139 // Set the PWM period, keeping the duty cycle the same.
bogdanm 19:398f4c622e1b 140 void pwmout_period_us(pwmout_t* obj, int us) {
bogdanm 19:398f4c622e1b 141 int i = 0;
bogdanm 20:4263a77256ae 142 uint32_t period_ticks;
bogdanm 19:398f4c622e1b 143
bogdanm 19:398f4c622e1b 144 timer_mr tid = pwm_timer_map[obj->pwm];
bogdanm 19:398f4c622e1b 145 LPC_TMR_TypeDef *timer = Timers[tid.timer];
bogdanm 19:398f4c622e1b 146 uint32_t old_period_ticks = timer->MR3;
bogdanm 20:4263a77256ae 147 period_ticks = (SystemCoreClock / 1000000 * us) / (timer->PR + 1);
bogdanm 20:4263a77256ae 148
bogdanm 19:398f4c622e1b 149 timer->TCR = TCR_RESET;
bogdanm 19:398f4c622e1b 150 timer->MR3 = period_ticks;
bogdanm 19:398f4c622e1b 151
bogdanm 19:398f4c622e1b 152 // Scale the pulse width to preserve the duty ratio
bogdanm 19:398f4c622e1b 153 if (old_period_ticks > 0) {
bogdanm 19:398f4c622e1b 154 for (i=0; i<3; i++) {
bogdanm 19:398f4c622e1b 155 uint32_t t_off = period_ticks - (uint32_t)(((uint64_t)timer->MR[i] * (uint64_t)period_ticks) / (uint64_t)old_period_ticks);
bogdanm 19:398f4c622e1b 156 timer->MR[i] = t_off;
bogdanm 19:398f4c622e1b 157 }
bogdanm 19:398f4c622e1b 158 }
bogdanm 19:398f4c622e1b 159 timer->TCR = TCR_CNT_EN;
bogdanm 19:398f4c622e1b 160 }
bogdanm 19:398f4c622e1b 161
bogdanm 19:398f4c622e1b 162 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
bogdanm 19:398f4c622e1b 163 pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
bogdanm 19:398f4c622e1b 164 }
bogdanm 19:398f4c622e1b 165
bogdanm 19:398f4c622e1b 166 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
bogdanm 19:398f4c622e1b 167 pwmout_pulsewidth_us(obj, ms * 1000);
bogdanm 19:398f4c622e1b 168 }
bogdanm 19:398f4c622e1b 169
bogdanm 19:398f4c622e1b 170 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
bogdanm 19:398f4c622e1b 171 timer_mr tid = pwm_timer_map[obj->pwm];
bogdanm 19:398f4c622e1b 172 LPC_TMR_TypeDef *timer = Timers[tid.timer];
bogdanm 20:4263a77256ae 173 uint32_t t_on = (uint32_t)((((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000) / (timer->PR + 1));
bogdanm 19:398f4c622e1b 174
bogdanm 19:398f4c622e1b 175 timer->TCR = TCR_RESET;
bogdanm 19:398f4c622e1b 176 if (t_on > timer->MR3) {
bogdanm 19:398f4c622e1b 177 pwmout_period_us(obj, us);
bogdanm 19:398f4c622e1b 178 }
bogdanm 19:398f4c622e1b 179 uint32_t t_off = timer->MR3 - t_on;
bogdanm 19:398f4c622e1b 180 timer->MR[tid.mr] = t_off;
bogdanm 19:398f4c622e1b 181 timer->TCR = TCR_CNT_EN;
bogdanm 19:398f4c622e1b 182 }