• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 100 subscribers
  • Views 137 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

J721EXCPXEVM: Using WKUP-UART0 as MAIN-UART0

J721EXCPXEVM: WKUP_UART relation with "System Firmware"

Santiago Pérez
Prodigy 130 points

Part Number: J721EXCPXEVM

Tool/software:

Hi,

This is a follow-up to this thread:
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1562893/j721excpxevm-using-wkup-uart0-as-main-uart0/6017302

To summarize, the discussion is about using WKUP_UART as a replacement for MAIN_UART0. Our assumption was that WKUP_UART could be used to display different boot logs since it is the first UART available when the processor powers up.

Our concern is the following:

If we use WKUP_UART both for boot logs and as the Linux terminal, could this have any impact on the system?

Since the device tree marks it as /* Wakeup UART is used by System firmware */, we are not entirely sure whether using it as the console could cause issues later on.

It would also be very helpful if you could share some references or documentation about what exactly the "System Firmware" is.


Thanks in advance,

  • 0
    TI__Guru 64995 points

    HI Santiago 

    System firmware (TIFS) executes on the M3 core. It is TI’s core security firmware that handles security services such as image authentication and firewall configuration.

    For debugging, you can enable TIFS tracing by modifying the default board configuration as described in the FAQ. When the TRACE_DST_UART0 flag is set in that configuration, TIFS routes its trace output to the wake‑up UART.

    Ideally it is not recommended to use wakeup UART for other logging, it may cause issue when you want to debug TIFS, as in current case two master controlling the same peripheral.

    Regards
    Diwakar