SPRACU5C June 2021 – September 2023 AM2431 , AM2432 , AM2434 , AM6411 , AM6412 , AM6421 , AM6422 , AM6441 , AM6442
Boot mode inputs do not have internal pullup or pulldown resistors that are active during processor power-up or reset. It is recommended to connect external pullup or pulldown resistors to set the required boot mode.
When dip switches are used, it is recommended to use a resistor divider ratio of 470 Ω (pullup) and 47 kΩ (pulldown) for improved noise performance.
When dip switches are not used, it is recommended to use a standard resistor (same value for pullup or pulldown) value Ex: 10 kΩ or similar since either a pullup or pulldown resistor is used.
It is recommended to terminate (pullup or pulldown) boot mode pins marked as Reserved or not used.
It is recommended to add provision for pullup and pulldown resistors for all the boot mode pins that have configuration capability for debugging, design flexibility and future enhancement. Populate either pullup or pulldown for each boot mode pins. Direct connection of boot mode pins to ground or power supply is not recommended or allowed since these IOs have alternate configuration and could intentionally or unintentionally be configured as output.
Based on the application requirement, a buffer that is only driven when reset is active (low) can be used to present the boot configuration to the processor.
If the processor IOs are configured as an output during normal operation, a current limiting series resistor (~1 kΩ) is recommended at the output of the buffers. See the device-specific EVM for implementation.