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2a210c157b
If the DAC peripheral has a mode register (DAC_MCR), it is set to normal mode with buffer enabled and connected to external pin and on-chip peripherals. This allows to measure the current value of a DAC channel or to use the DAC channel also for other on-chip peripherals.
139 lines
3.3 KiB
C
139 lines
3.3 KiB
C
/*
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* Copyright (C) 2014 Simon Brummer
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* 2015-2016 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_stm32
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* @ingroup drivers_periph_dac
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* @{
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*
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* @file
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* @brief Low-level DAC driver implementation
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*
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* @author Simon Brummer <simon.brummer@haw-hamburg.de>
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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*
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* @}
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*/
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#include "cpu.h"
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#include "assert.h"
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#include "periph/dac.h"
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/* DAC channel enable bits */
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#ifdef DAC_CR_EN2
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#define EN_MASK (DAC_CR_EN1 | DAC_CR_EN2)
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#else
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#define EN_MASK (DAC_CR_EN1)
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#endif
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/* get RCC bit */
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#if defined(RCC_APB1ENR_DAC1EN)
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#define RCC_BIT (RCC_APB1ENR_DAC1EN)
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#elif defined(RCC_APB1ENR1_DAC1EN)
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#define RCC_BIT (RCC_APB1ENR1_DAC1EN)
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#else
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#define RCC_BIT (RCC_APB1ENR_DACEN)
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#endif
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/* deduct DAC device from given line channel */
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static inline DAC_TypeDef *dev(dac_t line)
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{
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#if defined(DAC2)
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return (dac_config[line].chan > 1) ? DAC2 : DAC1;
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#elif defined (DAC1)
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(void) line;
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return DAC1;
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#else
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(void) line;
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return DAC;
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#endif
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}
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int8_t dac_init(dac_t line)
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{
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if (line >= DAC_NUMOF) {
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return DAC_NOLINE;
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}
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/* configure pin */
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gpio_init_analog(dac_config[line].pin);
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/* reset output and enable the line's channel */
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dac_poweron(line);
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dac_set(line, 0);
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return DAC_OK;
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}
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void dac_set(dac_t line, uint16_t value)
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{
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assert(line < DAC_NUMOF);
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#ifdef DAC_DHR12L2_DACC2DHR
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if (dac_config[line].chan & 0x01) {
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dev(line)->DHR12L2 = value;
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}
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else {
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dev(line)->DHR12L1 = value;
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}
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#else
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dev(line)->DHR12L1 = value;
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#endif
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}
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void dac_poweron(dac_t line)
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{
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assert(line < DAC_NUMOF);
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/* enable the DAC's clock */
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#if defined(DAC2)
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periph_clk_en(APB1, (dac_config[line].chan > 1) ?
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RCC_APB1ENR_DAC2EN : RCC_APB1ENR_DAC1EN);
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#else
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periph_clk_en(APB1, RCC_BIT);
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#endif
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#if VREFBUF_ENABLE && defined(VREFBUF_CSR_ENVR)
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/* enable VREFBUF if needed and available (for example if the board doesn't
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* have an external reference voltage connected to V_REF+), wait until
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* it is ready */
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RCC->APB2ENR |= RCC_APB2ENR_SYSCFGEN;
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VREFBUF->CSR &= ~VREFBUF_CSR_HIZ;
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VREFBUF->CSR |= VREFBUF_CSR_ENVR;
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while (!(VREFBUF->CSR & VREFBUF_CSR_VRR)) { }
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#endif
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#ifdef DAC_MCR_MODE1
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/* Normal mode with Buffer enabled and connected to external pin and on-chip
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* peripherals */
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dev(line)->MCR |= (DAC_MCR_MODE1_0 << (16 * (dac_config[line].chan & 0x01)));
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#endif
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/* enable corresponding DAC channel */
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dev(line)->CR |= (DAC_CR_EN1 << (16 * (dac_config[line].chan & 0x01)));
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}
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void dac_poweroff(dac_t line)
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{
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assert(line < DAC_NUMOF);
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/* disable corresponding channel */
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dev(line)->CR &= ~(DAC_CR_EN1 << (16 * (dac_config[line].chan & 0x01)));
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/* disable the DAC's clock in case no channel is active anymore */
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if (!(dev(line)->CR & EN_MASK)) {
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#if defined(DAC2)
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periph_clk_dis(APB1, (dac_config[line].chan > 1) ?
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RCC_APB1ENR_DAC2EN : RCC_APB1ENR_DAC1EN);
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#else
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periph_clk_dis(APB1, RCC_BIT);
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#endif
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}
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}
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