Skip to content

Latest commit

 

History

History
113 lines (79 loc) · 3.38 KB

dma_m2m_demo.rst

File metadata and controls

113 lines (79 loc) · 3.38 KB
Raw

DMA - Data Transfer Between RAM

This demo is based on the memory to memory mode of DMA for data transfer.

Hardware Connection

None

Software Implementation

  • For the code see examples/dma/dma_m2m
#define BSP_USING_DMA0_CH0

#if defined(BSP_USING_DMA0_CH0)
#ifndef DMA0_CH0_CONFIG
#define DMA0_CH0_CONFIG \
{   \
.id = 0, \
.ch = 0,\
.direction = DMA_MEMORY_TO_MEMORY,\
.transfer_mode = DMA_LLI_ONCE_MODE, \
.src_req = DMA_REQUEST_NONE, \
.dst_req = DMA_REQUEST_NONE, \
.src_width = DMA_TRANSFER_WIDTH_32BIT , \
.dst_width = DMA_TRANSFER_WIDTH_32BIT , \
}
#endif
#endif
  • Enable BSP_USING_DMA0_CH0 and configure the DMA device, see bsp/board/bl706_iot/peripheral_config.h
dma_register(DMA0_CH0_INDEX, "DMA", DEVICE_OFLAG_RDWR);

struct device *dma = device_find("DMA");

if (dma)
{
    device_open(dma, 0);
    device_set_callback(dma, dma_transfer_done);
    device_control(dma, DEVICE_CTRL_SET_INT, NULL);
}
  • First call the dma_register function to register a channel of the DMA device, currently register DMA_CH0
  • Then use the find function to find the handle corresponding to the device and save it in the dma handle
  • Finally use device_open to open the dma device in the default mode, call device_set_callback to register a dma channel 0 interrupt callback function, and call device_control to open the dma transmission completion interrupt
dma_reload(dma,(uint32_t)dma_src_buffer,(uint32_t)dma_dst_buffer,8000);
dma_channel_start(dma);
  • Call the dma_reload function to supplement the configuration of dma channel 0. A part of the configuration has been supplemented in DMA0_CH0_CONFIG. Here we mainly supplement the source data address, destination data address and total transmission length
  • Call dma_channel_start to start dma transmission
void dma_transfer_done(struct device *dev, void *args, uint32_t size, uint32_t state)
{
    uint32_t index=0;

    if(!state)
    {
        MSG("dma transfer task done\r\n");

        for(index=0;index<8000;index++){
            if(dma_dst_buffer[index]!=0xff){
                MSG("dma transfer error\r\n");
            }
        }

        MSG("dma transfer success\r\n");
    }

}
  • Check whether the data transmission is correct in the interrupt function

Compile and Program

 $ cd <sdk_path>/bl_mcu_sdk
 $ make BOARD=bl706_iot APP=dma_m2m

Experimental Phenomena

The data in the dma_src_buffer array is transferred to the dma_dst_buffer array through DMA channel 0 with a source 32-bit width and a target 32-bit width. After the data transfer is completed, the serial port prints dma transfer success.