mirror of https://github.com/ARMmbed/mbed-os.git
149 lines
4.4 KiB
C
149 lines
4.4 KiB
C
/***************************************************************************//**
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* @file analogout_aoi.c
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*******************************************************************************
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* @section License
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* <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
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*******************************************************************************
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************/
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#include "device.h"
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#if DEVICE_ANALOGOUT
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#include "mbed_assert.h"
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#include "mbed_error.h"
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#include "analogout_api.h"
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#include "pinmap.h"
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#include "pinmap_function.h"
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#include "PeripheralPins.h"
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#include "clocking.h"
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#include "em_dac.h"
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#include "em_cmu.h"
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static uint8_t dac_initialized = 0;
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void analogout_init(dac_t *obj, PinName pin)
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{
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/* init in-memory structure */
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obj->dac = (DAC_TypeDef *) pinmap_peripheral(pin, PinMap_DAC);
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MBED_ASSERT((unsigned int) obj->dac != NC);
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obj->channel = pin_location(pin, PinMap_DAC);
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MBED_ASSERT((unsigned int) obj->channel != NC);
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pin_mode(pin, Disabled);
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if (!dac_initialized) {
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/* Initialize the DAC. Will disable both DAC channels, so should only be done once */
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/* Use default settings */
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CMU_ClockEnable(cmuClock_DAC0, true);
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DAC_Init_TypeDef init = DAC_INIT_DEFAULT;
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/* Calculate the DAC clock prescaler value that will result in a DAC clock
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* close to 500kHz. Second parameter is zero. This uses the current HFPERCLK
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* frequency instead of setting a new one. */
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init.prescale = DAC_PrescaleCalc(500000, REFERENCE_FREQUENCY);
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/* Set reference voltage to VDD */
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init.reference = dacRefVDD;
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DAC_Init(obj->dac, &init);
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dac_initialized = 1;
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}
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/* Use default channel settings */
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DAC_InitChannel_TypeDef initChannel = DAC_INITCHANNEL_DEFAULT;
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initChannel.enable = true;
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DAC_InitChannel(obj->dac, &initChannel, obj->channel);
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}
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void analogout_free(dac_t *obj)
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{
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//Reset channel by re-initializing
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DAC_InitChannel_TypeDef initChannel = DAC_INITCHANNEL_DEFAULT;
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initChannel.enable = false;
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DAC_InitChannel(obj->dac, &initChannel, obj->channel);
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//Check all channels to see if we can disable the DAC completely
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if((DAC0->CH0CTRL & DAC_CH0CTRL_EN) == 0 && (DAC0->CH1CTRL & DAC_CH1CTRL_EN) == 0) {
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CMU_ClockEnable(cmuClock_DAC0, false);
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dac_initialized = 0;
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}
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}
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static inline void dac_write(dac_t *obj, int value)
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{
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switch (obj->channel) {
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case 0:
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obj->dac->CH0DATA = value;
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break;
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case 1:
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obj->dac->CH1DATA = value;
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break;
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}
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}
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static inline int dac_read(dac_t *obj)
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{
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switch (obj->channel) {
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case 0:
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return obj->dac->CH0DATA;
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break;
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case 1:
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return obj->dac->CH1DATA;
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break;
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default:
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error("AnalogOut pin error. Invalid channel");
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return -1;
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break;
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}
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}
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void analogout_write(dac_t *obj, float value)
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{
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/* We multiply the float value with 0xFFF because the DAC has 12-bit resolution.
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* Ie. accepts values between 0 and 0xFFF (4096). */
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dac_write(obj, value*0xFFF);
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}
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void analogout_write_u16(dac_t *obj, uint16_t value)
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{
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/* The DAC has 12 bit resolution, so we remove the 4 least significant bits */
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dac_write(obj, value >> 4);
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}
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float analogout_read(dac_t *obj)
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{
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/* dac_read returns a number between 0 and 0xFFF. Division gives us a float between 0 and 1 */
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return dac_read(obj)/(float)0xFFF;
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}
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uint16_t analogout_read_u16(dac_t *obj)
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{
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/* dac_read returns a number with 12 significant digits,
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* so we shift in 0s from right to make it a 16 bit number */
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return dac_read(obj) << 4;
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}
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const PinMap *analogout_pinmap()
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{
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return PinMap_DAC;
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}
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#endif
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