Boot change requirement in AM335x

Sandeep Tammana

Other Parts Discussed in Thread: AM3354, TPS65910, TPS65910A

Hello,

We are using AM3354BZCZ60 for our design which uses two flashes MMC1 and MMC0. One for main (OS and BOOT) and one for backup OS.

"We have a requirement that we need to boot from backup OS when there is a complete corruption of main flash"

In case of complete corruption of main flash, we have a circuit that gives a low pulse to PWRONRSTn of AM3354 with a press in push button and changes the boot configuration pins. So that system will reset and boot from back up OS.

Do you foresee any issues with this method as in general PWRONRSTn will be completely controlled by nRESPWRON pin of PMIC TPS65910. Here we have additional control

Please comment if there is a better way to achieve this req?

Regards,

Sandeep.

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi Sandeep,

At power-up time the TPS65910A PMIC sets both VDD_MPU and VDD_CORE voltages to 1.1V. Later on software may change these voltages according to OPP selected or via SmartReflex adjustment. The danger in toggling PWRONRSTn from another source is that the voltages may not be at 1.1V levels at boot time.

0 Sandeep Tammana over 10 years ago in reply to Biser Gatchev-XID

Intellectual 430 points

Thanks for your quick reply Biser.

We operate AM335x in OPP100 mode. In this case, we should be fine to held PWRONRSTn low independently as we maintain VDD_MPU and VDD_CORE voltages to 1.1V

Is there any other factor which limits us to use external power on reset circuit to change boot mode ?

Sandeep.

0 Biser Gatchev-XID over 10 years ago in reply to Sandeep Tammana

TI__Guru**** 393215 points

I forgot to mention that connecting an eMMC to MMC0 is a bad idea. Please refer to section 26.1.7.5.2 in the AM335X TRM Rev. K.

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Boot change requirement in AM335x