Johannes Stratmann / mbed-dev

added prescaler for 16 bit pwm in LPC1347 target

Fork of mbed-dev by mbed official

targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/analogout_api.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Child:
50:a417edff4437
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 /***************************************************************************//**
bogdanm 0:9b334a45a8ff 2 * @file analogout_aoi.c
bogdanm 0:9b334a45a8ff 3 *******************************************************************************
bogdanm 0:9b334a45a8ff 4 * @section License
bogdanm 0:9b334a45a8ff 5 * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
bogdanm 0:9b334a45a8ff 6 *******************************************************************************
bogdanm 0:9b334a45a8ff 7 *
bogdanm 0:9b334a45a8ff 8 * Permission is granted to anyone to use this software for any purpose,
bogdanm 0:9b334a45a8ff 9 * including commercial applications, and to alter it and redistribute it
bogdanm 0:9b334a45a8ff 10 * freely, subject to the following restrictions:
bogdanm 0:9b334a45a8ff 11 *
bogdanm 0:9b334a45a8ff 12 * 1. The origin of this software must not be misrepresented; you must not
bogdanm 0:9b334a45a8ff 13 * claim that you wrote the original software.
bogdanm 0:9b334a45a8ff 14 * 2. Altered source versions must be plainly marked as such, and must not be
bogdanm 0:9b334a45a8ff 15 * misrepresented as being the original software.
bogdanm 0:9b334a45a8ff 16 * 3. This notice may not be removed or altered from any source distribution.
bogdanm 0:9b334a45a8ff 17 *
bogdanm 0:9b334a45a8ff 18 * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
bogdanm 0:9b334a45a8ff 19 * obligation to support this Software. Silicon Labs is providing the
bogdanm 0:9b334a45a8ff 20 * Software "AS IS", with no express or implied warranties of any kind,
bogdanm 0:9b334a45a8ff 21 * including, but not limited to, any implied warranties of merchantability
bogdanm 0:9b334a45a8ff 22 * or fitness for any particular purpose or warranties against infringement
bogdanm 0:9b334a45a8ff 23 * of any proprietary rights of a third party.
bogdanm 0:9b334a45a8ff 24 *
bogdanm 0:9b334a45a8ff 25 * Silicon Labs will not be liable for any consequential, incidental, or
bogdanm 0:9b334a45a8ff 26 * special damages, or any other relief, or for any claim by any third party,
bogdanm 0:9b334a45a8ff 27 * arising from your use of this Software.
bogdanm 0:9b334a45a8ff 28 *
bogdanm 0:9b334a45a8ff 29 ******************************************************************************/
bogdanm 0:9b334a45a8ff 30
bogdanm 0:9b334a45a8ff 31 #include "device.h"
bogdanm 0:9b334a45a8ff 32 #if DEVICE_ANALOGOUT
bogdanm 0:9b334a45a8ff 33
bogdanm 0:9b334a45a8ff 34 #include "mbed_assert.h"
bogdanm 0:9b334a45a8ff 35 #include "error.h"
bogdanm 0:9b334a45a8ff 36 #include "analogout_api.h"
bogdanm 0:9b334a45a8ff 37 #include "pinmap.h"
bogdanm 0:9b334a45a8ff 38 #include "pinmap_function.h"
bogdanm 0:9b334a45a8ff 39 #include "PeripheralPins.h"
bogdanm 0:9b334a45a8ff 40 #include "clocking.h"
bogdanm 0:9b334a45a8ff 41
bogdanm 0:9b334a45a8ff 42 #include "em_dac.h"
bogdanm 0:9b334a45a8ff 43 #include "em_cmu.h"
bogdanm 0:9b334a45a8ff 44
bogdanm 0:9b334a45a8ff 45 uint8_t analogout_get_index(dac_t *obj)
bogdanm 0:9b334a45a8ff 46 {
bogdanm 0:9b334a45a8ff 47 return 0;
bogdanm 0:9b334a45a8ff 48 }
bogdanm 0:9b334a45a8ff 49
bogdanm 0:9b334a45a8ff 50 void analogout_preinit(dac_t *obj, PinName pin)
bogdanm 0:9b334a45a8ff 51 {
bogdanm 0:9b334a45a8ff 52 obj->dac = (DAC_TypeDef *) pinmap_peripheral(pin, PinMap_DAC);
bogdanm 0:9b334a45a8ff 53 MBED_ASSERT((int) obj->dac != NC);
bogdanm 0:9b334a45a8ff 54
bogdanm 0:9b334a45a8ff 55 obj->channel = pin_location(pin, PinMap_DAC);
bogdanm 0:9b334a45a8ff 56 MBED_ASSERT((int) obj->channel != NC);
bogdanm 0:9b334a45a8ff 57 }
bogdanm 0:9b334a45a8ff 58
bogdanm 0:9b334a45a8ff 59 void analogout_init(dac_t *obj, PinName pin)
bogdanm 0:9b334a45a8ff 60 {
bogdanm 0:9b334a45a8ff 61 static uint8_t dac_initialized = 0;
bogdanm 0:9b334a45a8ff 62
bogdanm 0:9b334a45a8ff 63 /* init in-memory structure */
bogdanm 0:9b334a45a8ff 64 analogout_preinit(obj, pin);
bogdanm 0:9b334a45a8ff 65
bogdanm 0:9b334a45a8ff 66 if (!dac_initialized) {
bogdanm 0:9b334a45a8ff 67 /* Initialize the DAC. Will disable both DAC channels, so should only be done once */
bogdanm 0:9b334a45a8ff 68 /* Use default settings */
bogdanm 0:9b334a45a8ff 69 CMU_ClockEnable(cmuClock_DAC0, true);
bogdanm 0:9b334a45a8ff 70
bogdanm 0:9b334a45a8ff 71 DAC_Init_TypeDef init = DAC_INIT_DEFAULT;
bogdanm 0:9b334a45a8ff 72
bogdanm 0:9b334a45a8ff 73 /* Calculate the DAC clock prescaler value that will result in a DAC clock
bogdanm 0:9b334a45a8ff 74 * close to 500kHz. Second parameter is zero. This uses the current HFPERCLK
bogdanm 0:9b334a45a8ff 75 * frequency instead of setting a new one. */
bogdanm 0:9b334a45a8ff 76 init.prescale = DAC_PrescaleCalc(500000, REFERENCE_FREQUENCY);
bogdanm 0:9b334a45a8ff 77
bogdanm 0:9b334a45a8ff 78 /* Set reference voltage to VDD */
bogdanm 0:9b334a45a8ff 79 init.reference = dacRefVDD;
bogdanm 0:9b334a45a8ff 80
bogdanm 0:9b334a45a8ff 81 DAC_Init(obj->dac, &init);
bogdanm 0:9b334a45a8ff 82 dac_initialized = 1;
bogdanm 0:9b334a45a8ff 83 }
bogdanm 0:9b334a45a8ff 84 /* Use default channel settings */
bogdanm 0:9b334a45a8ff 85 DAC_InitChannel_TypeDef initChannel = DAC_INITCHANNEL_DEFAULT;
bogdanm 0:9b334a45a8ff 86 DAC_InitChannel(obj->dac, &initChannel, obj->channel);
bogdanm 0:9b334a45a8ff 87
bogdanm 0:9b334a45a8ff 88
bogdanm 0:9b334a45a8ff 89 }
bogdanm 0:9b334a45a8ff 90
bogdanm 0:9b334a45a8ff 91 void analogout_enable(dac_t *obj, uint8_t enable)
bogdanm 0:9b334a45a8ff 92 {
bogdanm 0:9b334a45a8ff 93 DAC_Enable(obj->dac, obj->channel, enable);
bogdanm 0:9b334a45a8ff 94 }
bogdanm 0:9b334a45a8ff 95
bogdanm 0:9b334a45a8ff 96 void analogout_pins_enable(dac_t *obj, uint8_t enable)
bogdanm 0:9b334a45a8ff 97 {
bogdanm 0:9b334a45a8ff 98 //not avail for EFM32
bogdanm 0:9b334a45a8ff 99 }
bogdanm 0:9b334a45a8ff 100
bogdanm 0:9b334a45a8ff 101 static inline void dac_write(dac_t *obj, int value)
bogdanm 0:9b334a45a8ff 102 {
bogdanm 0:9b334a45a8ff 103 switch (obj->channel) {
bogdanm 0:9b334a45a8ff 104 case 0:
bogdanm 0:9b334a45a8ff 105 obj->dac->CH0DATA = value;
bogdanm 0:9b334a45a8ff 106 break;
bogdanm 0:9b334a45a8ff 107 case 1:
bogdanm 0:9b334a45a8ff 108 obj->dac->CH1DATA = value;
bogdanm 0:9b334a45a8ff 109 break;
bogdanm 0:9b334a45a8ff 110 }
bogdanm 0:9b334a45a8ff 111 }
bogdanm 0:9b334a45a8ff 112
bogdanm 0:9b334a45a8ff 113 static inline int dac_read(dac_t *obj)
bogdanm 0:9b334a45a8ff 114 {
bogdanm 0:9b334a45a8ff 115 switch (obj->channel) {
bogdanm 0:9b334a45a8ff 116 case 0:
bogdanm 0:9b334a45a8ff 117 return obj->dac->CH0DATA;
bogdanm 0:9b334a45a8ff 118 break;
bogdanm 0:9b334a45a8ff 119 case 1:
bogdanm 0:9b334a45a8ff 120 return obj->dac->CH1DATA;
bogdanm 0:9b334a45a8ff 121 break;
bogdanm 0:9b334a45a8ff 122 default:
bogdanm 0:9b334a45a8ff 123 error("AnalogOut pin error. Invalid channel");
bogdanm 0:9b334a45a8ff 124 return -1;
bogdanm 0:9b334a45a8ff 125 break;
bogdanm 0:9b334a45a8ff 126 }
bogdanm 0:9b334a45a8ff 127 }
bogdanm 0:9b334a45a8ff 128
bogdanm 0:9b334a45a8ff 129 void analogout_write(dac_t *obj, float value)
bogdanm 0:9b334a45a8ff 130 {
bogdanm 0:9b334a45a8ff 131 /* We multiply the float value with 0xFFF because the DAC has 12-bit resolution.
bogdanm 0:9b334a45a8ff 132 * Ie. accepts values between 0 and 0xFFF (4096). */
bogdanm 0:9b334a45a8ff 133 dac_write(obj, value*0xFFF);
bogdanm 0:9b334a45a8ff 134 }
bogdanm 0:9b334a45a8ff 135
bogdanm 0:9b334a45a8ff 136 void analogout_write_u16(dac_t *obj, uint16_t value)
bogdanm 0:9b334a45a8ff 137 {
bogdanm 0:9b334a45a8ff 138 /* The DAC has 12 bit resolution, so we remove the 4 least significant bits */
bogdanm 0:9b334a45a8ff 139 dac_write(obj, value >> 4);
bogdanm 0:9b334a45a8ff 140 }
bogdanm 0:9b334a45a8ff 141
bogdanm 0:9b334a45a8ff 142 float analogout_read(dac_t *obj)
bogdanm 0:9b334a45a8ff 143 {
bogdanm 0:9b334a45a8ff 144 /* dac_read returns a number between 0 and 0xFFF. Division gives us a float between 0 and 1 */
bogdanm 0:9b334a45a8ff 145 return dac_read(obj)/(float)0xFFF;
bogdanm 0:9b334a45a8ff 146 }
bogdanm 0:9b334a45a8ff 147
bogdanm 0:9b334a45a8ff 148 uint16_t analogout_read_u16(dac_t *obj)
bogdanm 0:9b334a45a8ff 149 {
bogdanm 0:9b334a45a8ff 150 /* dac_read returns a number with 12 significant digits,
bogdanm 0:9b334a45a8ff 151 * so we shift in 0s from right to make it a 16 bit number */
bogdanm 0:9b334a45a8ff 152 return dac_read(obj) << 4;
bogdanm 0:9b334a45a8ff 153 }
bogdanm 0:9b334a45a8ff 154
bogdanm 0:9b334a45a8ff 155 #endif