1.2.3 SAM-BA® Monitor

The ROM code sends the RomBOOT character string to the target UART console. If no valid bootstrap is found on the external Flash memory specified in the boot sequence, the ROM code enters the SAM-BA Monitor. To determine which communication link to use, the ROM code waits for either a USB enumeration from the host computer connected to the target USB interface or for a character to be received on the UART console interface. Once the communication interface is identified, the SAM-BA Monitor waits for and responds to commands from the host computer on this interface only.