SPC56EL54 - RESET pin is always pulled down by the CPU

[GabiPaz-GSP]

Hi

On power up the SPC56EL54L5CBFS looks like it is in an internal RESET mode that does not  end. 

The RESET pin is always  pulled down by the CPU. 

Power up of 1.2v and 3.3v in 1.5msec.

 

Can you help to to understand why the RESET pin is always  pulled down by the CPU?

 

Thank you.

[Peter BENSCH]

Welcome @GabiPaz-GSP, to the community!

The RESET pin has an internal pull-down. What have you connected externally to the RESET pin?

Regards
/Peter

[GabiPaz-GSP]

Hi Peter

Thank you, hope that you can help.

1K as pull-up and 10nF  to GND.

The 1.2v and 3.3v provided with 2 DC/DC converters.

 

[Peter BENSCH]

OK, at least externally RESET is obviously wired correctly.

However, RESET is a bidirectional pin whose internal open drain can be activated by various internal sources. As no information on software etc. is currently available, nobody can make a statement.

[GabiPaz-GSP]

Hi Peter 

After some testing,

 Internal RESET released after  Power up sequence.   

The Power up sequence should be as following:  3.3V , 1.2v PLL , delay : +500uS - 1.2v Core 

Can you please advice if this  Power up sequence OK?

Gabi

[Peter BENSCH]

As far as I know, the order does not play a role during power up, you can also switch them on simultaneously.