#define BUFFERSIZE 64
uint8_t RxBuffer[BUFFERSIZE] = { 0 };

DMA_InitTypeDef  DMA_InitStructure;

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)(&USART1->DR);
DMA_InitStructure.DMA_MemoryBaseAddr     = (uint32_t)(RxBuffer);
DMA_InitStructure.DMA_DIR                = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize         = sizeof(RxBuffer) / sizeof(RxBuffer[0]);
DMA_InitStructure.DMA_PeripheralInc      = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc          = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;
DMA_InitStructure.DMA_MemoryDataSize     = DMA_MemoryDataSize_Byte;
DMA_InitStructure.DMA_Mode               = DMA_Mode_Circular;   // ring buffer
DMA_InitStructure.DMA_Priority           = DMA_Priority_Medium;
DMA_InitStructure.DMA_M2M                = DMA_M2M_Disable;

// DMA1_Channel5 -> CD00171190.pdf page 282, table 78
DMA_Init(DMA1_Channel5, &DMA_InitStructure);
DMA_Cmd(DMA1_Channel5, ENABLE);

USART_DMACmd(USART1, USART_DMAReq_Rx, ENABLE);
USART_Cmd(USART1, ENABLE);

uint16_t posNow = 0, posFIFO = 0;

// last write value position in buffer
posNow = (sizeof(RxBuffer) / sizeof(RxBuffer[0])) - DMA_GetCurrDataCounter(DMA1_Channel5);

// print buffer
while (posFIFO != posNow) {
    char ch = RxBuffer[posFIFO++];
    print("%c",ch);
    // buffer end
    if (posFIFO == (sizeof(RxBuffer) / sizeof(RxBuffer[0]))) { posFIFO = 0; }
}