现在想将一个值为0的数组，循环的复制到一个图像区域，即对图像区域的值清零，那么在MDMA配置中应该注意什么，我配置如下，但是不能正常工作。

oMDMASrcDesc.nStartAddress = (uint32_t)&nZeroFillVal[0];
    oMDMASrcDesc.nDMAConfig = (uint32_t)(ENUM_DMA_CFG_ADDR2D
        |ENUM_DMA_CFG_FETCH06
        |ENUM_DMA_CFG_STOP
        |ENUM_DMA_CFG_MSIZE08
        |ENUM_DMA_CFG_PSIZE04
        |ENUM_DMA_CFG_READ
        |ENUM_DMA_CFG_EN);
    oMDMASrcDesc.nXCount = ((uint32_t)480 * 3u)/8u;
    oMDMASrcDesc.nXModify = 0u;
    oMDMASrcDesc.nYCount = (uint32_t)272;
    oMDMASrcDesc.nYModify = 0u;