4.1 Writing the Boot Configuration Word (BCW) to the Backup Register BUREGx to Enable JTAG and Serial UART Console

The default JTAG port and UART interface configured in the ROM code do not correspond to the appropriate IOSET for the SAMA5D29-Curiosity board. To enable the appropriate IOSET, use the SAM-BA commands below to configure the JTAG port and UART interface.

  1. Write the Boot Configuration Word to the backup register BUREG0.

    sam-ba -p serial -d sama5d29 -a bootconfig -c writecfg:bureg0:JTAG_IOSET3,UART0_IOSET1

    Note: The user can write the Boot Configuration Word in other backup registers by replacing BUREG0 in the above command with BUREG1, BUREG2, BUREG3 and validate the same registers in the command given below.
  2. Validate the Boot Configuration Word to save the configuration in the backup register BUREG0.

    sam-ba -p serial -d sama5d29 -a bootconfig -c writecfg:bscr:bureg0,valid

  3. Read the Boot Configuration Word from the backup register BUREG0.

    sam-ba -p serial -d sama5d29 -a bootconfig -c readcfg:bureg0

  4. Connect the USB-TTL cable to UART DEBUG (J28) on the SAMA5D29-Curiosity board.
  5. Open any serial terminal in your PC and select the appropriate com port.

  6. Once connected successfully, reset the board. The terminal displays RomBOOT.