SPRADO2 November 2024 AM62A3 , AM62A3-Q1 , AM62A7 , AM62A7-Q1
In the SK, the boot mode pins BOOTMODE [15:00] are asserted through two isolation buffers. The buffers verify that the SYSBOOT pulls (boot mode configured using resistors) control the level of the signals when the boot mode signals are latched (around the PORz_OUT rising edge) by the processor. Since boot mode signals are used for other functions after processor power-up and are connected to attached devices or peripherals, isolate the boot mode configuration resistors from other connected peripherals so that the other connected peripherals do not conflict with the intended boot mode configuration (signal levels).
The buffers are enabled when PORz_OUT is driven low by the processor. Once PORz_OUT is asserted, the buffer outputs are Hi-Z so the signals are not pulled or influenced by the boot mode resistors.
For optimizing the design (including BOM), optimize or delete the buffers,depending on the use case. The boot mode pull resistors value are selectable so that the resistors do not affect the operation of attach devices.