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AM625: AM62X-SKEVM Boot Modes description is bad

Martin Vana
Intellectual 470 points

Part Number: AM625

The Boot Mode SW settings description in the User's Guide SPRUJ40 is rather confusing.

The section 2.5.16.2 vaguely states that 
"The boot mode orientation has changed between E1 and E2. Please follow board silkscreen."
as well as 
"Note: Actual Board Silkscreen May Appear Inverted in this Orientation. Follow Physical Switch Text"
To add to the possible confusion the UG shows 
"Figure 2-7. Bootmode Switch Configuration for SD Boot (E1)"

I understand that board layout mistakes happen and are hard to fix. However, the lack of a clear description with corresponding figure in the User Guide is something that is hard to forgive.

In essence: The switches SW1 and SW2 are located and oriented (ON-OFF) as described in the UG. However, the bit assignment on each of the switches is mirrored with LSB on the left side and MSB on the right side. (that makes B15 adjacent to B0).

I hope this may help. If you just started with an EVM that never worked and you are not even sure if you flashed proper image on the uSD card then you may easily bur an hour or more in a trial/error mode.
What adds to it is the fact that pressing RESET button doesn't seem to re-read the SW configuration. One needs to power-cycle the EVM every time the configuration is changed.

"Follow board silkscreen?" = Look for tiny B0, B7, B8 and B16. Once you know what to look for it is obvious - but magnifying glass may be your friend.
Cheers - Martin



  • 0
    TI__Guru 70822 points

    Hi Martin, we appreciate your feedback on opportunities to improve the getting started document. The owner of this document is currently out of the office. Please allow until early next week for a response. Thanks.

  • 0 in reply to Andreas Dannenberg
    Intellectual 470 points

    Hi Andreas,
    Thanks for passing it along. TI documentation have always been the "golden standard of quality" and that is why I occasionally submit feedback as I see the value ;-)
    To be fair - the Quick Start Guide has a photo of the switches that is correct and even mentions "Please make sure the EVM is powered off when changing the boot mode switches." This statement is perhaps less informative than "Boot mode switches are read only during EVM power-up (not during system reset)".

    However, the User's Guide https://www.ti.com/lit/ug/spruj40/spruj40.pdf is the document that doesn't clarify the mirrored layout and the fact that reset is not sufficient to register the switch state if changed and full power cycle is needed.

    Closing this issue since the feedback reached destination and will be more than happy to respond directly if desired.
    Thanks - M.