19.1.1 Overview

By default, the chip starts in Standard Boot mode. See Secure Boot Strategy for details on Secure Boot mode enabling.

The system always boots from the ROM memory at address 0x0.

The ROM code is a boot program contained in the embedded ROM. It is also called “Bootloader”.

Note: JTAG access is disabled during execution of the ROM code. It is enabled when jumping into SRAM when a valid code has been found on an external Non-Volatile Memory (NVM) at the same time the ROM memory access is locked. If no valid bootstrap is found on an external NVM, the ROM code enables the USB connection and one UART serial port, starts the standard monitor, locks access to the ROM memory and enables the JTAG connection.