AM2432: Boot Related Questions

Mari Tsunoda

Expert 5726 points

Part Number: AM2432

Hi Team,

I received this question from one of my customers.

Setting primary bootmode:SPI and backup bootmode:UART, on this condition, if we cut CS0 line of SPI flash(ex. using DIPSW on board), what happens? we expect the behavior of ROM on CPU as follows:
primary boot failed so, try backup boot.

background of the question:
we expect usages as follow:
usually boot from SPI flash. when we want to update bootcode on SPI flash, boot with special bootcode via UART, then re-write SPI flash using UART-booted bootcode.
See AM64/AM243x TRM igure 4-3. Boot Process.
When SPI Flash doesn't response on SPI boot, how long does it take to be judged as "Ingtegrity check No"?
On Figure 4-3, "DSMC Watchdog Timer Timeout?(3min)" means ROM code continues primary boot and backup boot for 3 minutes. is it right?

Best regards,

Mari Tsunoda

over 3 years ago

0 Ming Wei over 3 years ago

TI__Guru 55165 points

Hi Mari,

Those two questions are tough to answer, because I do not know how the ROM bootloader will behave if there is not CS0 to reach the OSPI flash.

There is a POLL_EXP_INT_FLD (bit 13) event in OSPI_IRQ_STATUS_REG. It may cause an interrupt, after certain amount of time passed, but I am not 100% sure.

I will pass this question to our OSPI flash expert for him to comment further.

Best regards,

Ming

0 Mari Tsunoda over 3 years ago in reply to Ming Wei

TI__Expert 5726 points

Hi Ming,

Thanks for your response.

Ming Wei said:
There is a POLL_EXP_INT_FLD (bit 13) event in OSPI_IRQ_STATUS_REG. It may cause an interrupt, after certain amount of time passed, but I am not 100% sure.

Noted.

Best regards,

Mari

0 Mari Tsunoda over 3 years ago in reply to Ming Wei

TI__Expert 5726 points

Hi Ming,

Any update or comment from the OSPI flash expert?

Best regards,

Mari

0 Mari Tsunoda over 3 years ago in reply to Ming Wei

TI__Expert 5726 points

Hi Ming,

Please let me know if there is any update on this.

Best regards,

Mari Tsunoda

0 Anand Mahadevan SS over 3 years ago in reply to Mari Tsunoda

TI__Expert 8165 points

Hi Mari,

I need some details here, will you be using the SPI bootmode or xSPI/OSPI bootmode for the ROM to boot? Because depending on that the route taken by ROM will be different. There might be flash configurations done by ROM in case of xSPI boot.

In any case, ROM will attempt to read from the zero offset of the flash if the bootmode is SPI/OSPI/xSPI. If there is no CS line, I am assuming that the read will fail and will return all zeros and ROM should fall back to the backup boot mode. I am not sure what would be the delay in this case, but this is the expected behaviour. Let me know if you need any more details.

Regards,
Anand Mahadevan SS

0 Mari Tsunoda over 3 years ago in reply to Anand Mahadevan SS

TI__Expert 5726 points

Hi Anand,

Thanks for your reply. They are interested in using the SPI bootmode. Would it be possible for you to tell me the delay until Integrity Check is deemed No? If not, I will let the customer know.

Best regards,

Mari Tsunoda

0 Mari Tsunoda over 3 years ago in reply to Mari Tsunoda

TI__Expert 5726 points

Hi Anand,

Any update on this? Pending response since my escalation.

Best regards,

Mari Tsunoda

0 Aakash Kedia over 2 years ago in reply to Mari Tsunoda

TI__Mastermind 26145 points

Hi Mari,

ROM checks the Primary Location first, and then searches for the backup location. If the Backup location also does not contain the valid x509 certificate then the ROM fall backs to UART boot mode.

Best Regards,
Aakash

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AM2432: Boot Related Questions