97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
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/** \file
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\brief Analog subsystem, ARM specific part.
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*/
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#if defined TEACUP_C_INCLUDE && defined __ARM_STM32F411__
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#include "cmsis-stm32f4xx.h"
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#include "arduino.h"
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#include "temp.h"
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/** Inititalise the analog subsystem.
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Initialise the ADC and start hardware scan loop for all used sensors.
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*/
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void analog_init() {
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if (NUM_TEMP_SENSORS) { // At least one channel in use.
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PIOC_2_PORT->MODER |= (GPIO_MODER_MODER0 << ((PIOC_2_PIN) << 1)); // analog mode
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PIOC_2_PORT->PUPDR &= ~(3 << ((PIOC_2_PIN) << 1)); // no pullup
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PIOC_2_PORT->OSPEEDR |= (3 << ((PIOC_2_PIN) << 1)); // high speed
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RCC->APB2ENR |= RCC_APB2ENR_ADC1EN; //Enable clock
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/* Set ADC parameters */
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/* Set the ADC clock prescaler */
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/* Datasheet says max. ADC-clock is 36MHz
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We don't need that much. 12MHz is slowest possible.
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*/
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ADC->CCR |= (ADC_CCR_ADCPRE);
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/* Set ADC scan mode */
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// scan mode disabled
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// reset resolution
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// discontinous mode disabled
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ADC1->CR1 &= ~( ADC_CR1_SCAN |
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ADC_CR1_RES |
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ADC_CR1_DISCEN);
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/* Set ADC resolution */
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// resoltion 10bit
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ADC1->CR1 |= ADC_CR1_RES_0;
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/* Set ADC data alignment */
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// reset = right align
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// reset external trigger
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//
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// disable continous conversion mode
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// disable ADC DMA continuous request
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// disable ADC end of conversion selection
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ADC1->CR2 &= ~( ADC_CR2_ALIGN |
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ADC_CR2_EXTSEL |
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ADC_CR2_EXTEN |
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ADC_CR2_CONT |
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ADC_CR2_DDS |
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ADC_CR2_EOCS);
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/* Set ADC number of conversion */
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// 1 conversion
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ADC1->SQR1 &= ~(ADC_SQR1_L);
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}
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}
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/** Read analog value.
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\param channel Channel to be read.
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\return Analog reading, 10-bit right aligned.
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STM32F4 goes a different way. The ADC don't have a register for
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each channel. We need a DMA soon to convert and hold all datas.
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*/
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//#include "delay.h"
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uint16_t analog_read(uint8_t index) {
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// 11.8.2 Managing a sequence of conversions without using the DMA
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// page 220
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ADC1->SMPR1 &= ~(ADC_SMPR1_SMP12); // PIOC_2_ADC 12
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// 3 CYCLES
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ADC1->SQR3 &= ~(ADC_SQR3_SQ1); // rank 1
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ADC1->SQR3 |= PIOC_2_ADC; // << (5 * (rank - 1))
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ADC1->CR2 |= ADC_CR2_ADON // A/D Converter ON / OFF
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| ADC_CR2_SWSTART; // Start Conversion of regular channels
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while (!(ADC1->SR & ADC_SR_EOC) == ADC_SR_EOC);
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return ADC1->DR;
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}
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#endif /* defined TEACUP_C_INCLUDE && defined __ARM_STM32F411__ */
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