Electronic – stm32f303 ADC continuous conversion mode multi-channel does not auto start new sequence

I am using a STM32F303v with 2 ADC regular channels in cotinuous mode with a DMA and would like continuous conversion to take place in order to enable a stream of data.

Base on the setup of my DMA and ADC below, I am unable to perform continuous conversion. On further debugging, I found that the very first conversion is successful and then the ADSTART bit is set back to 0. If I manually set ADSTART=1, the conversion starts, DMA does the transfer when it finishes and then ADSTART goes back to 0. Please help.

DMAy_x = DMA1_Channel1;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)dest;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_BufferSize = 2; // in data unit
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&ADCx->DR;
    DMA_Init(DMAy_x, &DMA_InitStructure);
    DMA_Cmd(DMAy_x, ENABLE);
    ADCx = ADC1;
    ADC_Cmd(ADCx, DISABLE);
    while(ADCx->CR & ADC_CR_ADEN);
    ADC_DeInit(ADCx);
    ADC_InitTypeDef ADC_InitStructure;
    ADC_StructInit(&ADC_InitStructure);
    ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
    ADC_InitStructure.ADC_NbrOfRegChannel = 2;
    ADC_InitStructure.ADC_ExternalTrigEventEdge = ADC_ExternalTrigEventEdge_None;
    ADC_InitStructure.ADC_ExternalTrigConvEvent = ADC_ExternalTrigConvEvent_0;
    ADC_InitStructure.ADC_OverrunMode = ENABLE;
    ADC_InitStructure.ADC_AutoInjMode = DISABLE;

    ADC_Init(ADCx, &ADC_InitStructure);

    // Set up ADC channels
    for (uint16_t i = 0; i < nPins; ++i)
    {
        // make them regular channels with rank i +1, sample time is 19 ADC cycles
        ADC_RegularChannelConfig(ADCx, PIN_MAP[pinNames[i]].adcChannel, i + 1, ADC_SAMPLE_TIME); 
    }
    ADC_DMAConfig(ADCx, ADC_DMAMode_Circular);
    ADC_DMACmd(ADCx, ENABLE);
    // Enable everything
    ADC_Cmd(ADCx, ENABLE);
    while (!(ADC_GetFlagStatus(ADCx, ADC_FLAG_RDY)));
    ADC_StartConversion(ADCx);