STM32f103 ADC with DMA

#include "adc.h"

#define ADC_DATA_SIZE 320

#define ADC_PERIOD (SystemCoreClock / 1000) / 2

#define ADCx ADC1
#define ADC_Channel_n ADC_Channel_7
#define RCC_APBnPeriph_ADCx RCC_APB2Periph_ADC1
#define ADC_RCC_APBnPeriphClockCmd RCC_APB2PeriphClockCmd
#define ADC_ExternalTrigConv_Tn_trigger ADC_ExternalTrigConv_T3_TRGO

#define GPIOx GPIOA
#define GPIO_Pin_n GPIO_Pin_7
#define RCC_APBnPeriph_GPIOx RCC_APB2Periph_GPIOA
#define GPIO_RCC_APBnPeriphClockCmd RCC_APB2PeriphClockCmd

#define TIMx TIM3
#define TIM_RCC_APBnPeriphClockCmd RCC_APB1PeriphClockCmd
#define RCC_APBnPeriph_TIMx RCC_APB1Periph_TIM3

#define DMAn_Channeln_IRQn DMA1_Channel1_IRQn
#define DMAn_IT_TCn DMA1_IT_TC1
#define DMAn_Channeln DMA1_Channel1
#define RCC_AHBPeriph_DMAn RCC_AHBPeriph_DMA1

static u16 adcDmaData[ADC_DATA_SIZE];

u16 *ADC_getData() { return adcDmaData; }

void timer_config(void) {
  TIM_TimeBaseInitTypeDef tim;
  TIM_RCC_APBnPeriphClockCmd(RCC_APBnPeriph_TIMx, ENABLE);

  /* Time base configuration */
  TIM_TimeBaseStructInit(&tim);
  tim.TIM_Period = (u16)(ADC_PERIOD / 125 - 1);  // 875 - 1;
  tim.TIM_Prescaler = 0;
  tim.TIM_ClockDivision = 0;
  tim.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIMx, &tim);

  TIM_SelectOutputTrigger(TIMx, TIM_TRGOSource_Update);
}

void timer_start(void) { TIM_Cmd(TIMx, ENABLE); }

void timer_stop(void) { TIM_Cmd(TIMx, DISABLE); }

void dma_init() {
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMAn, ENABLE);
  // DMA
  DMA_InitTypeDef dma;
  DMA_StructInit(&dma);

  dma.DMA_BufferSize = ADC_DATA_SIZE;
  dma.DMA_MemoryBaseAddr = (u32)adcDmaData;
  dma.DMA_PeripheralBaseAddr = (u32) & (ADCx->DR);
  dma.DMA_Mode = DMA_Mode_Circular;
  dma.DMA_Priority = DMA_Priority_High;
  dma.DMA_MemoryInc = DMA_MemoryInc_Enable;
  dma.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  dma.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_Init(DMAn_Channeln, &dma);

  NVIC_EnableIRQ(DMAn_Channeln_IRQn);
  DMA_ITConfig(DMAn_Channeln, DMA_IT_TC, ENABLE);
  DMA_Cmd(DMAn_Channeln, ENABLE);
}

void gpio_init() {
  GPIO_RCC_APBnPeriphClockCmd(RCC_APBnPeriph_GPIOx, ENABLE);

  GPIO_InitTypeDef gpio;
  gpio.GPIO_Speed = GPIO_Speed_50MHz;
  gpio.GPIO_Pin = GPIO_Pin_n;
  gpio.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_Init(GPIOx, &gpio);
}

void adc_init() {
  // clock for ADC (max 14MHz --> 72/6=12MHz)
  // TODO: check for maximum clock
  // RCC_ADCCLKConfig(RCC_PCLK2_Div2);
  ADC_RCC_APBnPeriphClockCmd(RCC_APBnPeriph_ADCx, ENABLE);

  // ADC
  ADC_InitTypeDef adc;
  adc.ADC_ScanConvMode = DISABLE;
  adc.ADC_ContinuousConvMode = DISABLE;
  adc.ADC_ExternalTrigConv = ADC_ExternalTrigConv_Tn_trigger;
  adc.ADC_DataAlign = ADC_DataAlign_Right;
  adc.ADC_Mode = ADC_Mode_Independent;
  adc.ADC_NbrOfChannel = 1;
  ADC_Init(ADCx, &adc);

  ADC_RegularChannelConfig(ADCx, ADC_Channel_n, 1, ADC_SampleTime_1Cycles5);

  ADC_Cmd(ADCx, ENABLE);  // enable ADCx

  // Calibration
  ADC_ResetCalibration(ADCx);  // Reset previous calibration
  while (ADC_GetResetCalibrationStatus(ADCx))
    ;
  ADC_StartCalibration(
      ADCx);  // Start new calibration (ADC must be off at that time)
  while (ADC_GetCalibrationStatus(ADCx))
    ;

  ADC_ExternalTrigConvCmd(ADCx, ENABLE);
  ADC_DMACmd(ADCx, ENABLE);
  ADC_Cmd(ADCx, ENABLE);
}

void ADC_init() {
  gpio_init();
  dma_init();
  adc_init();
  timer_config();
  timer_start();
}

static u8 dataAvailable = 0;

inline u8 isDataAvailable() { return dataAvailable; }

inline void markDataUsed() {
  dataAvailable = 0;
  timer_start();
}

void DMA1_Channel1_IRQHandler(void) {
  if (DMA_GetITStatus(DMAn_IT_TCn) == SET) {
    //        DMA_Cmd(DMA1_Channel1, DISABLE);
    DMA_ClearITPendingBit(DMAn_IT_TCn);
    timer_stop();
    dataAvailable = 1;
  }
}