AM2432: Power off and power on with Uart connected, jump to backup boot mode

Hello Zekun

Thank you for the query.

Customer needs to verify IO compatibility - if the 3.3V used for the logic is same as the IO supply for the IO group referenced by the UART 

Is customer expecting the UART interface data to be available when the SOC supplies are off. The SOC IOs are not fail-safe and no inputs should be applied before the SOC supply ramps

Regards,

Sreenivasa

Hello Zekun

Please refer below updated inputs.

Kallikuppa Sreenivasa said:

Customer needs to verify IO compatibility - if the 3.3V used for the logic is same as the IO supply for the IO group referenced by the UART 

Customer needs to verify IO compatibility - if the 3.3V used for the logic IC is same as the IO supply for the IO group  (VDDSHVx) referenced by the SOC UART interface pins.

Regards,

Sreenivasa

Hi Sreenivasa:

   Zekun sending  the wrong message to you，we use the logic IC is no problem，this HW design there is problem,As shown in the figure below，but  power of CH430 of USB-TTL  supply by PC's USB interface.

，

Hello zhanglongc 

Thank you for the inputs.

SOC IOs are not fail-safe. No input should be applied before supply ramps.

I assume the logic IC is powered by the IO supply that connects to the SOC.

Regards,

Sreenivasa

Hi Sreenivasa:

   1、So AM2432 jumped  go into backup boot (UART mode) when Power off and power on，Reasons for the USB-TTL  input to the AM2432 UART port before supply ramps?What's the harm in that?

 2、I'd also like to know why this problem is causing AM2432 jumped  go into backup boot (UART mode)。

Hello zhanglongc 

Thank you.

SOC IOs are not fail-safe. 

If the inputs are applied to any of the SOC IOs before the supply ramps, this could cause voltage feed that could affect the power supply or SOC performance.

I will need the complete schematics to be able to specifically answer the reason.

Regards,

Sreenivasa