SPRAD21I May 2022 – September 2025 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP , AM62A1-Q1 , AM62A3 , AM62A3-Q1 , AM62A7 , AM62A7-Q1 , AM62D-Q1 , AM62P , AM62P-Q1
In the SK, the boot mode inputs BOOTMODE[15:00] are configured using x2 buffers (for isolation). The buffers make sure that the SYSBOOT pulls (pullup and/or pulldown) (boot mode configuration resistors) control the IO level of the signals when the boot mode inputs are latched (during PORz_OUT rising edge). The boot mode configuration resistors are isolated from other connected peripherals (since boot mode input pins have alternate functions) so that the other connected peripherals do not conflict with the intended boot mode configuration (IO levels).
The buffers are enabled when PORz_OUT is low. Once PORz_OUT is deasserted (goes high), the buffer outputs are in Hi-Z state.
For optimizing the custom board design (including BOM), the boot mode buffers can be optimized or deleted (use case dependent, custom board designer to verify). The recommendation is to select the pull resistors value, so that the resistors do not affect the operation of the attach devices.