In functional mode, the bootloading of an image from the SDF is the first bootmode attempted by the bootloader. This bootmode involves the following steps:

1. Pinmux the QSPI pins of the AWR294x device:
   • QSPI[0]: Ball U11
   • QSPI[1]: Ball V11
   • QSPI[2]: Ball T11
   • QSPI_CLK: Ball R10
   • QSPI_CS: Ball U12
2. QSPI is set up to operate at (system clock / 5) = (200/5) = 40 MHz.
3. The sFLASH discoverable parameters (SFDP) command is issued to retrieve the JEDEC compliant response, which includes information regarding the sFLASH capabilities and command set. When the SFDP response is received, the information is used to communicate with the SDF and further interpret the contents and load the images. For more information on the flash variants supported with AWR294x/AWR2544 devices please refer to the application note.

Key points

• The RBL performs the read from the SDF, based on the highest capability mode (quad, dual, or single) as published by the SDF in response to the SFDP command.
• For SDF variants that support quad mode, the quad mode commands are issued; if the quad enable (QE) bit is not set, the communication fails. In such cases, the load flow assumes that the QE bit in the SDF is already set.
• SBL is user implemented entity which has logic to achieve above mentioned flow. SBL can use any interface out of UART, CANFD or Ethernet if required.
• Fallback images: the RBL supports loading of images from the following locations only as a fallback Mechanism, if one of the images is corrupted in the SDF. The locations of the images are:
  • – META IMG1(SDF offset – 0x0)
  • – META IMG2(SDF offset – 0x40000)