STM32F205 uses TIM_DMA_Update event of timer 8 to trigger DMA2 circularly. In fact, DMA only executes once？

STM32F205 uses the TIM_DMA_Update event loop of timer 8 to trigger DMA2 transport, which moves 5 data from test_data to dest_arr at a time.

Using DMA2_Stream1_Channel7, start these two functions in the main program, configure DMA and TIM8, and then observe that the value of test_data changes to 0x06030444.

When test_data is cleared after a period of delay, the timer can enter the interrupt normally, but DMA no longer works. Test_data is always zero, and I don't know what the problem is.

Please help me to analyze it.

unsigned int dest_arr;

unsigned int test_data[5] = {0x06030440,0x06030441,0x06030442,0x06030443,0x06030444};

/*DMA configuration*/

void DMA_Auto_Config(void)

{   

    DMA_InitTypeDef DMA_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2,ENABLE);      

    DMA_DeInit(DMA2_Stream1);

    while (DMA_GetCmdStatus(DMA2_Stream1) ! = DISABLE){}  // wait DMA2_Stream1 disable

    DMA_InitStructure.DMA_Channel = DMA_Channel_7;    // select DMA_Channel_7

    DMA_InitStructure.DMA_PeripheralBaseAddr  = (uint32_t)(test_data);     // source address

    DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)(&dest_arr);     // Destination address

    DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToMemory;  // MemoryToMemory

    DMA_InitStructure.DMA_BufferSize = 5;                                 

    DMA_InitStructure.DMA_PeripheralInc  = DMA_PeripheralInc_Enable;   

    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Disable;  

    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;     

    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;    

    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;                 

    DMA_InitStructure.DMA_Priority = DMA_Priority_High;                

    DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;      

    DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;

    DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;            

    DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;   

    DMA_Init(DMA2_Stream1, &DMA_InitStructure);     

    DMA_Cmd(DMA2_Stream1, ENABLE); 

}

/*timer8 configuration*/

void timer8_init(void)

{

    GPIO_InitTypeDef GPIO_InitStructure;

    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

    TIM_OCInitTypeDef TIM_OCInitStructure;     

    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8, ENABLE);

    TIM_TimeBaseStructure.TIM_Period = 100-1;                                             

    TIM_TimeBaseStructure.TIM_Prescaler = 60000-1;                                         

    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;

    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

    TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure);

    NVIC_InitStructure.NVIC_IRQChannel = TIM8_UP_TIM13_IRQn;                          

    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  

    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;  

    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  

    NVIC_Init(&NVIC_InitStructure);  

    TIM_ClearFlag(TIM8,TIM_FLAG_Update);

    TIM_ITConfig(TIM8, TIM_IT_Update, ENABLE);                                   // Enable TIM8 IRQ

    TIM8->CR2 |= TIM_CR2_CCDS;

    TIM_DMACmd(TIM8,TIM_DMA_Update,ENABLE);

    TIM_Cmd(TIM8,ENABLE);

}

/*Main*/

int main(void) 

{     

    uart5_init();

    timer8_init();                                 

    DMA_Auto_Config();                     

    delay_ms(100);

    test_arr = 0;              

    while(1)

    {         

        delay_ms(100);

        printf("dest_arr = 0x%x\n",dest_arr);

    }

    return 0;

}

/*TIM8 irq*/

void TIM8_UP_TIM13_IRQHandler(void)

{

    if(TIM_GetITStatus(TIM8,TIM_IT_Update)==SET)                             

    {

        TIM_Cmd(TIM8, DISABLE);

        TIM_ClearITPendingBit(TIM8,TIM_IT_Update);                                // ClearITPendingBit

        printf("TIMER_8 IRQ IRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQ!\n");

        delay_ms(100);

        TIM_Cmd(TIM8, ENABLE);

    }

}

Output：（Dest_arr is always 0） 

        dest_arr = 0x0

        TIMER_8 IRQ IRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQ!

        TIMER_8 IRQ IRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQ!

        TIMER_8 IRQ IRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQ!

        dest_arr= 0x0

        TIMER_8 IRQ IRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQIRQ!