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Last commit 20 Feb 2019 by mbed official

targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/pwmout_api.c@627:4fa1328d9c60, 2015-09-25 (annotated)

Committer:
mbed_official
Date:
Fri Sep 25 14:15:10 2015 +0100
Revision:
627:4fa1328d9c60
Parent:
556:a217bc785985 
Synchronized with git revision fe238a91ab7a4d1d72c4cab9da04967c619d54ad



Full URL: https://github.com/mbedmicro/mbed/commit/fe238a91ab7a4d1d72c4cab9da04967c619d54ad/



Silicon Labs - Add support for low-power async Serial

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 627:4fa1328d9c60 1 /***************************************************************************//**
mbed_official 627:4fa1328d9c60 2 * @file pwmout_api.c
mbed_official 627:4fa1328d9c60 3 *******************************************************************************
mbed_official 627:4fa1328d9c60 4 * @section License
mbed_official 627:4fa1328d9c60 5 * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
mbed_official 627:4fa1328d9c60 6 *******************************************************************************
mbed_official 525:c320967f86b9 7 *
mbed_official 627:4fa1328d9c60 8 * Permission is granted to anyone to use this software for any purpose,
mbed_official 627:4fa1328d9c60 9 * including commercial applications, and to alter it and redistribute it
mbed_official 627:4fa1328d9c60 10 * freely, subject to the following restrictions:
mbed_official 525:c320967f86b9 11 *
mbed_official 627:4fa1328d9c60 12 * 1. The origin of this software must not be misrepresented; you must not
mbed_official 627:4fa1328d9c60 13 * claim that you wrote the original software.
mbed_official 627:4fa1328d9c60 14 * 2. Altered source versions must be plainly marked as such, and must not be
mbed_official 627:4fa1328d9c60 15 * misrepresented as being the original software.
mbed_official 627:4fa1328d9c60 16 * 3. This notice may not be removed or altered from any source distribution.
mbed_official 525:c320967f86b9 17 *
mbed_official 627:4fa1328d9c60 18 * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
mbed_official 627:4fa1328d9c60 19 * obligation to support this Software. Silicon Labs is providing the
mbed_official 627:4fa1328d9c60 20 * Software "AS IS", with no express or implied warranties of any kind,
mbed_official 627:4fa1328d9c60 21 * including, but not limited to, any implied warranties of merchantability
mbed_official 627:4fa1328d9c60 22 * or fitness for any particular purpose or warranties against infringement
mbed_official 627:4fa1328d9c60 23 * of any proprietary rights of a third party.
mbed_official 627:4fa1328d9c60 24 *
mbed_official 627:4fa1328d9c60 25 * Silicon Labs will not be liable for any consequential, incidental, or
mbed_official 627:4fa1328d9c60 26 * special damages, or any other relief, or for any claim by any third party,
mbed_official 627:4fa1328d9c60 27 * arising from your use of this Software.
mbed_official 627:4fa1328d9c60 28 *
mbed_official 627:4fa1328d9c60 29 ******************************************************************************/
mbed_official 525:c320967f86b9 30
mbed_official 525:c320967f86b9 31 #include "device.h"
mbed_official 525:c320967f86b9 32 #include "clocking.h"
mbed_official 525:c320967f86b9 33 #if DEVICE_PWMOUT
mbed_official 525:c320967f86b9 34
mbed_official 525:c320967f86b9 35 #include "mbed_assert.h"
mbed_official 525:c320967f86b9 36 #include "pwmout_api.h"
mbed_official 525:c320967f86b9 37 #include "cmsis.h"
mbed_official 525:c320967f86b9 38 #include "pinmap.h"
mbed_official 525:c320967f86b9 39 #include "PeripheralPins.h"
mbed_official 525:c320967f86b9 40 #include "device_peripherals.h"
mbed_official 544:1af5f1c39e80 41 #include "sleepmodes.h"
mbed_official 525:c320967f86b9 42
mbed_official 525:c320967f86b9 43 #include "em_cmu.h"
mbed_official 525:c320967f86b9 44 #include "em_gpio.h"
mbed_official 525:c320967f86b9 45 #include "em_timer.h"
mbed_official 525:c320967f86b9 46
mbed_official 544:1af5f1c39e80 47 static int pwm_prescaler_div;
mbed_official 525:c320967f86b9 48
mbed_official 548:1abac31e188e 49 uint32_t pwmout_get_channel_route(pwmout_t *obj)
mbed_official 548:1abac31e188e 50 {
mbed_official 548:1abac31e188e 51 MBED_ASSERT(obj->channel != (PWMName) NC);
mbed_official 525:c320967f86b9 52
mbed_official 548:1abac31e188e 53 switch (obj->channel) {
mbed_official 548:1abac31e188e 54 case PWM_CH0:
mbed_official 548:1abac31e188e 55 return TIMER_ROUTE_CC0PEN;
mbed_official 548:1abac31e188e 56 break;
mbed_official 548:1abac31e188e 57 case PWM_CH1:
mbed_official 548:1abac31e188e 58 return TIMER_ROUTE_CC1PEN;
mbed_official 548:1abac31e188e 59 break;
mbed_official 548:1abac31e188e 60 case PWM_CH2:
mbed_official 548:1abac31e188e 61 return TIMER_ROUTE_CC2PEN;
mbed_official 548:1abac31e188e 62 break;
mbed_official 548:1abac31e188e 63 default:
mbed_official 548:1abac31e188e 64 return 0;
mbed_official 548:1abac31e188e 65 }
mbed_official 525:c320967f86b9 66 }
mbed_official 525:c320967f86b9 67
mbed_official 525:c320967f86b9 68 void pwmout_enable_pins(pwmout_t *obj, uint8_t enable)
mbed_official 525:c320967f86b9 69 {
mbed_official 525:c320967f86b9 70 if (enable) {
mbed_official 525:c320967f86b9 71 pin_mode(obj->pin, PushPull);
mbed_official 525:c320967f86b9 72 } else {
mbed_official 525:c320967f86b9 73 // TODO_LP return PinMode to the previous state
mbed_official 525:c320967f86b9 74 pin_mode(obj->pin, Disabled);
mbed_official 525:c320967f86b9 75 }
mbed_official 525:c320967f86b9 76 }
mbed_official 525:c320967f86b9 77
mbed_official 525:c320967f86b9 78 void pwmout_enable(pwmout_t *obj, uint8_t enable)
mbed_official 525:c320967f86b9 79 {
mbed_official 548:1abac31e188e 80 /* Start with default CC (Compare/Capture) channel parameters */
mbed_official 548:1abac31e188e 81 TIMER_InitCC_TypeDef timerCCInit = TIMER_INITCC_DEFAULT;
mbed_official 525:c320967f86b9 82 if (enable) {
mbed_official 525:c320967f86b9 83 /* Set mode to PWM */
mbed_official 525:c320967f86b9 84 timerCCInit.mode = timerCCModePWM;
mbed_official 544:1af5f1c39e80 85 }
mbed_official 525:c320967f86b9 86
mbed_official 544:1af5f1c39e80 87 /* Configure CC channel */
mbed_official 544:1af5f1c39e80 88 TIMER_InitCC(PWM_TIMER, obj->channel, &timerCCInit);
mbed_official 525:c320967f86b9 89 }
mbed_official 525:c320967f86b9 90
mbed_official 544:1af5f1c39e80 91 void pwmout_init(pwmout_t *obj, PinName pin)
mbed_official 544:1af5f1c39e80 92 {
mbed_official 548:1abac31e188e 93 obj->channel = (PWMName) pinmap_peripheral(pin, PinMap_PWM);
mbed_official 548:1abac31e188e 94 obj->pin = pin;
mbed_official 548:1abac31e188e 95 MBED_ASSERT(obj->channel != (PWMName) NC);
mbed_official 544:1af5f1c39e80 96
mbed_official 548:1abac31e188e 97 /* Turn on clock */
mbed_official 548:1abac31e188e 98 CMU_ClockEnable(PWM_TIMER_CLOCK, true);
mbed_official 544:1af5f1c39e80 99
mbed_official 548:1abac31e188e 100 /* Turn on timer */
mbed_official 548:1abac31e188e 101 if(!(PWM_TIMER->STATUS & TIMER_STATUS_RUNNING)) {
mbed_official 548:1abac31e188e 102 TIMER_Init_TypeDef timerInit = TIMER_INIT_DEFAULT;
mbed_official 548:1abac31e188e 103 TIMER_Init(PWM_TIMER, &timerInit);
mbed_official 548:1abac31e188e 104 }
mbed_official 544:1af5f1c39e80 105
mbed_official 544:1af5f1c39e80 106 /* Enable correct channel */
mbed_official 548:1abac31e188e 107 uint32_t routeloc = pwmout_get_channel_route(obj);
mbed_official 548:1abac31e188e 108 if(PWM_TIMER->ROUTE & routeloc) {
mbed_official 548:1abac31e188e 109 //This channel was already in use
mbed_official 548:1abac31e188e 110 //TODO: gracefully handle this case
mbed_official 548:1abac31e188e 111 } else {
mbed_official 548:1abac31e188e 112 //This channel was unused up to now
mbed_official 548:1abac31e188e 113 PWM_TIMER->ROUTE |= routeloc;
mbed_official 548:1abac31e188e 114 blockSleepMode(EM1);
mbed_official 544:1af5f1c39e80 115
mbed_official 548:1abac31e188e 116 //TODO: check if any channel was up already, then don't re-init timer
mbed_official 548:1abac31e188e 117 pwmout_enable(obj, true);
mbed_official 548:1abac31e188e 118 pwmout_enable_pins(obj, true);
mbed_official 548:1abac31e188e 119 }
mbed_official 544:1af5f1c39e80 120
mbed_official 544:1af5f1c39e80 121 /* Route correct channel to location 1 */
mbed_official 544:1af5f1c39e80 122 PWM_TIMER->ROUTE &= ~_TIMER_ROUTE_LOCATION_MASK;
mbed_official 544:1af5f1c39e80 123 PWM_TIMER->ROUTE |= PWM_ROUTE;
mbed_official 544:1af5f1c39e80 124
mbed_official 544:1af5f1c39e80 125 /* Set default 20ms frequency and 0ms pulse width */
mbed_official 544:1af5f1c39e80 126 pwmout_period(obj, 0.02);
mbed_official 544:1af5f1c39e80 127 }
mbed_official 544:1af5f1c39e80 128
mbed_official 548:1abac31e188e 129 void pwmout_free(pwmout_t *obj)
mbed_official 548:1abac31e188e 130 {
mbed_official 548:1abac31e188e 131 uint32_t routeloc = pwmout_get_channel_route(obj);
mbed_official 548:1abac31e188e 132 if(PWM_TIMER->ROUTE & routeloc) {
mbed_official 548:1abac31e188e 133 //This channel was in use, so disable
mbed_official 548:1abac31e188e 134 PWM_TIMER->ROUTE &= ~routeloc;
mbed_official 548:1abac31e188e 135 pwmout_enable_pins(obj, false);
mbed_official 548:1abac31e188e 136 unblockSleepMode(EM1);
mbed_official 544:1af5f1c39e80 137
mbed_official 548:1abac31e188e 138 //TODO: check if all channels are down, then switch off timer
mbed_official 548:1abac31e188e 139 } else {
mbed_official 548:1abac31e188e 140 //This channel was disabled already
mbed_official 548:1abac31e188e 141 }
mbed_official 544:1af5f1c39e80 142 }
mbed_official 525:c320967f86b9 143
mbed_official 525:c320967f86b9 144 void pwmout_write(pwmout_t *obj, float value)
mbed_official 525:c320967f86b9 145 {
mbed_official 525:c320967f86b9 146 if (value < 0.0f) {
mbed_official 525:c320967f86b9 147 value = 0;
mbed_official 525:c320967f86b9 148 } else if (value > 1.0f) {
mbed_official 525:c320967f86b9 149 value = 1;
mbed_official 525:c320967f86b9 150 }
mbed_official 525:c320967f86b9 151
mbed_official 556:a217bc785985 152 float pulse_period_in_s = obj->period_cycles / ((float) (REFERENCE_FREQUENCY >> pwm_prescaler_div));
mbed_official 525:c320967f86b9 153 pwmout_pulsewidth(obj, value * pulse_period_in_s);
mbed_official 525:c320967f86b9 154 }
mbed_official 525:c320967f86b9 155
mbed_official 525:c320967f86b9 156 float pwmout_read(pwmout_t *obj)
mbed_official 525:c320967f86b9 157 {
mbed_official 525:c320967f86b9 158 return obj->width_cycles / (float) obj->period_cycles;
mbed_official 525:c320967f86b9 159 }
mbed_official 525:c320967f86b9 160
mbed_official 525:c320967f86b9 161 // Set the PWM period, keeping the absolute pulse width the same.
mbed_official 525:c320967f86b9 162 void pwmout_period(pwmout_t *obj, float seconds)
mbed_official 525:c320967f86b9 163 {
mbed_official 525:c320967f86b9 164 // Find the lowest prescaler divider possible.
mbed_official 525:c320967f86b9 165 // This gives us max resolution for a given period
mbed_official 525:c320967f86b9 166
mbed_official 525:c320967f86b9 167 //The value of the top register if prescaler is set to 0
mbed_official 556:a217bc785985 168 int cycles = REFERENCE_FREQUENCY * seconds;
mbed_official 544:1af5f1c39e80 169 pwm_prescaler_div = 0;
mbed_official 525:c320967f86b9 170
mbed_official 525:c320967f86b9 171 //The top register is only 16 bits, so we keep dividing till we are below 0xFFFF
mbed_official 525:c320967f86b9 172 while (cycles > 0xFFFF) {
mbed_official 525:c320967f86b9 173 cycles /= 2;
mbed_official 544:1af5f1c39e80 174 pwm_prescaler_div++;
mbed_official 525:c320967f86b9 175
mbed_official 544:1af5f1c39e80 176 //Max pwm_prescaler_div supported is 10
mbed_official 544:1af5f1c39e80 177 if (pwm_prescaler_div > 10) {
mbed_official 544:1af5f1c39e80 178 pwm_prescaler_div = 10;
mbed_official 525:c320967f86b9 179 cycles = 0xFFFF; //Set it to max possible value;
mbed_official 525:c320967f86b9 180 break;
mbed_official 525:c320967f86b9 181 }
mbed_official 525:c320967f86b9 182 }
mbed_official 525:c320967f86b9 183
mbed_official 525:c320967f86b9 184 obj->period_cycles = cycles;
mbed_official 525:c320967f86b9 185
mbed_official 525:c320967f86b9 186 //Set prescaler
mbed_official 544:1af5f1c39e80 187 PWM_TIMER->CTRL = (PWM_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) | (pwm_prescaler_div << _TIMER_CTRL_PRESC_SHIFT);
mbed_official 525:c320967f86b9 188
mbed_official 525:c320967f86b9 189 /* Set Top Value, which controls the PWM period */
mbed_official 525:c320967f86b9 190 TIMER_TopSet(PWM_TIMER, obj->period_cycles);
mbed_official 525:c320967f86b9 191 }
mbed_official 525:c320967f86b9 192
mbed_official 525:c320967f86b9 193 void pwmout_period_ms(pwmout_t *obj, int ms)
mbed_official 525:c320967f86b9 194 {
mbed_official 525:c320967f86b9 195 pwmout_period(obj, ms / 1000.0f);
mbed_official 525:c320967f86b9 196 }
mbed_official 525:c320967f86b9 197
mbed_official 525:c320967f86b9 198 void pwmout_period_us(pwmout_t *obj, int us)
mbed_official 525:c320967f86b9 199 {
mbed_official 556:a217bc785985 200 pwmout_period(obj, us / 1000000.0f);
mbed_official 525:c320967f86b9 201 }
mbed_official 525:c320967f86b9 202
mbed_official 525:c320967f86b9 203 void pwmout_pulsewidth(pwmout_t *obj, float seconds)
mbed_official 525:c320967f86b9 204 {
mbed_official 556:a217bc785985 205 obj->width_cycles = (uint32_t) (((float) (REFERENCE_FREQUENCY >> pwm_prescaler_div)) * seconds);
mbed_official 525:c320967f86b9 206 TIMER_CompareBufSet(PWM_TIMER, obj->channel, obj->width_cycles);
mbed_official 525:c320967f86b9 207 }
mbed_official 525:c320967f86b9 208
mbed_official 525:c320967f86b9 209 void pwmout_pulsewidth_ms(pwmout_t *obj, int ms)
mbed_official 525:c320967f86b9 210 {
mbed_official 556:a217bc785985 211 obj->width_cycles = (uint32_t) ((REFERENCE_FREQUENCY >> pwm_prescaler_div) * ms) / 1000;
mbed_official 556:a217bc785985 212 TIMER_CompareBufSet(PWM_TIMER, obj->channel, obj->width_cycles);
mbed_official 525:c320967f86b9 213 }
mbed_official 525:c320967f86b9 214
mbed_official 525:c320967f86b9 215 void pwmout_pulsewidth_us(pwmout_t *obj, int us)
mbed_official 525:c320967f86b9 216 {
mbed_official 556:a217bc785985 217 obj->width_cycles = (uint32_t) ((REFERENCE_FREQUENCY >> pwm_prescaler_div) * us) / 1000000;
mbed_official 556:a217bc785985 218 TIMER_CompareBufSet(PWM_TIMER, obj->channel, obj->width_cycles);
mbed_official 525:c320967f86b9 219 }
mbed_official 525:c320967f86b9 220
mbed_official 525:c320967f86b9 221 #endif