DS90UB940-Q1: How to exit the Ultra Low Power State (ULPS)?

Augus,
The Twakeup is "Time that a transmitter drives a Mark-1 state prior to a Stop state in order to initiate an exit from ULPS", it is set automatically by UB940 based on "specification for D-PHY". It is controlled by the logical PHY-protocol. Also, you can see the minimum time of Twakeup is 1ms based on "specification of D-PHY".

best regards,
Steven

So, I make UB940 enter ULPS by setting the register 0x6A and it will automatially exit the ULPS when locked again to serializer? Is it right?

The ULPS is processed by the DPHY protocol definition, you can't configure the ULPS mode. All are done automatically by the link design (chip internally detects it), you are not required to configure them.

best regards,
Steven

Hi Steven, how do I understand the following in the 940 datasheet:
The DS90UB940-Q1 supports the MIPI defined Ultra-Low Power State (ULPS). DS90UB940-Q1 D-PHY lanes
will enter ULPS mode upon software standby mode through 0x6A [2] generated by the processor.

This means UB940 can enter ULPS based on register setting. also, when your processor is paired with UB940, the D-PHY is mipi spec. 1.2 compatible.

best regards,
Steven