摄像头dma采集数据，突然只能传输一次数据 求指教

petime

这个是我的dma初始化
void dma_init()
{
asm("nop");
volatile uint8 *tempptr1;
SIM_SCGC6 |= SIM_SCGC6_DMAMUX_MASK;//打开SMA多路复用时钟
SIM_SCGC7|=SIM_SCGC7_DMA_MASK;      //打开ＤＭＡ模块时钟
DMAMUX_CHCFG5|=DMAMUX_CHCFG_SOURCE(51);
DMAMUX_CHCFG5 |= DMAMUX_CHCFG_ENBL_MASK;//DMA channel is enabled
tempptr1 = &Image[0][Line_max-1];
DMA_SADDR(5)  =(uint32)&GPIOB_PDIR;//设置源地址GPIO口，PORTB
DMA_DADDR(5)=(uint32_t)tempptr1;//0X400FF0CC;  
DMA_NBYTES_MLNO(5) = DMA_NBYTES_MLNO_NBYTES(1);//每次读取一字节
DMA_NBYTES_MLOFFNO(5)=1;//Number of bytes to be transferred in each service request of the channel.
DMA_NBYTES_MLOFFYES(5)=1;//Number of bytes to be transferred in each service request of the channe
DMA_ATTR(5) = DMA_ATTR_SSIZE(0) | DMA_ATTR_DSIZE(0); //源数据宽度8bit，目的数据宽度8bit
DMA_SOFF(5) = 0;//每次传送源地址不变
DMA_DOFF(5)= -1;//每次写目的地址减1
DMA_SLAST(5) =0 ;//2*4次之后回到初始地//主循环结束后源地址0回写tcd
DMA_TCD5_BITER_ELINKNO=DMA_BITER_ELINKNO_BITER(Line_max);
DMA_TCD5_CITER_ELINKNO=DMA_CITER_ELINKNO_CITER(Line_max);
DMA_DLAST_SGA(5) = 0; //每次传输完成后向后推进一个byte
DMA_ERQ&=~DMA_ERQ_ERQ5_MASK ;//The DMA request signal for the corresponding channel is enabled
}

void portc_isr(void)
{

  
  if(PORTC_PCR8&PORT_PCR_ISF_MASK)  //herf  
  {
        Row_count ++;
     PORTC_PCR8|=PORT_PCR_ISF_MASK;   
    if  ((Row_count>=10) && (Row_count==Gather_Row[Gather_Row_count]) && (Row_count<=240)&&Gather_Row_count<Row_max)   
     {
    // tempptr = tempptr;
     DMA_SADDR(5)  =(uint32)&GPIOB_PDIR;
     DMA_DADDR(5)=(uint32_t)&Image[m][Line_max-1];//0X400FF0CC; //0X400FF0C8; //ADDRESS OF PTD_PTOR   
     DMA_CDNE=DMA_CDNE_CDNE(5); //Clears the corresponding bit in TCDn_CSR[DONE]
     DMA_ERQ|= DMA_ERQ_ERQ5_MASK ;  
     m++;         
      Gather_Row_count++;   
     }
  }  
   
  if(PORTC_PCR10&PORT_PCR_ISF_MASK) // sync
  {
   
     Gather_Row_end=1;
     m=0;
     Row_count = 0;
     Gather_Row_count=0;
     Get_speed_cunt=0;     
     PORTC_PCR10|=PORT_PCR_ISF_MASK;
  }
现象 ：  dma只传输一次
以前好使的了，这几天就突然不好使了，把摄像头直接连在单片机上，依然这样，排出了硬件原因