2.3.6 Boot

• Double check that the boot configuration pins are set to the correct option.
• Use external pull resistors. Do not tie boot pins directly to ground or VDD.
• It is highly recommended to have some population options to be able to easily change the reset mode. This can be handy in a variety of circumstances. For example, if you were doing a NOR flash boot and you ever accidentally put in some bad code, you might end up in a scenario where you can't connect to the device with emulator because it is in a bad state, and you can't reprogram the flash as a result! Having an alternate boot mode can be a life saver.
• Read carefully the initialization section in the device-specific Technical Reference Manual. You may have to deal with important information that can change your design. Look for which chip select is used by default, default clock setups, bus widths, wait states, supported booting devices, initial fetch address and interrupt vector addresses, default memory map and so on.
• For OMAPL137/C6747 devices, the UART boot mode requires the input clock (OSCIN) to run at 24 MHz.

CAUTION

Be careful if anything external is hooked up to boot pins (such as when the pins are multiplexed with GPIO or other peripherals). You must make sure that the boot pins are at the proper levels when power-on reset occurs, such that the correct values are latched in order for the device to boot correctly.