Boot Mode pins provide means to select the boot mode and options before the device is powered up. After every POR, they are the main source to populate the Boot Parameter Tables. See Section 5.6, Boot Parameter Tables for table list and description.
Boot mode pins can be divided into the following categories:
- BOOTMODE[02:00] – Denote system clock
frequency (MCU_OSC0_XI/XO) to ROM code for PLL configuration.
- BOOTMODE[06:03] – Select the requested boot (primary) mode after POR, that is, the peripheral/memory to boot from.
- BOOTMODE[09:07] – These pins provide optional configurations for primary boot and are used in conjunction with the boot mode selected.
- BOOTMODE[12:10] – Select the backup boot mode, that is, the peripheral/memory to boot from, if primary boot device failed.
- BOOTMODE[13] – This pin provides optional configurations for the backup boot devices.
- BOOTMODE[15:14] – Reserved pins.
Note: It is user's responsibility to set the
boot mode pins (via pullups or pulldowns, and jumpers/switches) depending on the desired
boot scenario.