SPRZ457I January 2021 – December 2024 AM2431 , AM2432 , AM2434 , AM6411 , AM6412 , AM6421 , AM6422 , AM6441 , AM6442
Boot: ROM does not properly select OSPI clocking modes based on BOOTMODE
The ROM bootloader only selects an internal loopback mode for SPI/QSPI/OSPI/xSPI boot, regardless of the Iclk field value selected by the BOOTMODE pins (see the device specific TRM for BOOTMODE pin mappings), which is intended to allow the user to choose an internal or external clocking method. This results in less flexibility in board topology in customers designs. Customers intending to use the external board loopback mode could see timing issues in ROM boot because the external loopback clock is not being used.
The topology of the OSPI design must not use "External Board Loopback" if planning to use OSPI as a boot source. All other clocking topologies (including internal loopback or DQS) can be used. Refer to the device specific datasheet, section "Applications, Implementation, and Layout" for supported clocking topologies using OSPI.