AWR2188 will judge whether it is QSPI mode or SPI/I2C mode based on SOP during the RBL stage. If it is QSPI mode, AWR2188 copies the DFP image from Flash to AWR2188's RAM; if it is SPI/I2C mode, the external processor needs to transmit the DFP image to AWR2188 via SPI or I2C. Below, taking the SPI mode as an example, the DFP image download is introduced.

    /* Offset in the M0 flash where the metaimage for the 2188 is stored*/
    imagecfg.w_ImageSrcAddress = 0x6F80;
    /* Size of the metaimage*/
    imagecfg.w_ImageSize = 0x32F48; 
    status = ml_rblImageDownload(DEVICE_INDEX,&imagecfg);
    while(status!=0);

The external processor will download the DFP image into AWR2188 through this function ml_rblImageDownload. There are two points to note when using this function to download the image:

1. The address of the image in the external processor: the location of the DFP image on the Flash or external processor side;
2. The size of the image. For example, the image size is 208712 Bytes, and the sample code uses hexadecimal to represent the size, which is 0x32F48.

Generally speaking, the downloaded firmware is the DFP firmware package provided by TI, and the local storage path is: "C:\ti\mmWave_DFP_04_00_xx_xx\firmware\xWR2188\metaimage\mmwave_dfp_metaimage.bin".

After downloading the image, AWR2188 will return a verification value, saved in the structure T_ML_MSS_APPLICATION_ENTRY_RSP.w_ParseStatus. Users can judge whether the image download is normal based on this return value. If the image is downloaded normally to AWR2188, this verification value is 0x3E1A95C5.

Since the image download and subsequent control are all completed through the SPI/I2C protocol, the SPI/I2C protocol analysis of AWR2188 is placed in Chapter 4 for separate discussion.