SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
There are several low-power scenarios which consist of switching off various parts of the design:
When D-PHY and DSI are both shut-down and the display is powered down, the restart is a normal start procedure as described in Section 12.6.4.7.3, Start-up procedure.
When only the D-PHY is stopped, it is placed in either the stop or ULP state. Restarting the D-PHY is similar to the regular start-up procedure, however, after the lanes are enabled by the DSI Controller (clklane_en, dat1_en, dat2_en, dat3_en and dat4_en in register mctl_main_en are set), the D-PHY generates a rising edge on the stopstate signal to indicate to the DSI Controller that the enable request has been effective within the D-PHY. After that the start-up procedure may continue up to the point that the DSI link is ready to begin transmission.
Note that when setting the D-PHY into the ULP state, the application needs to wait enough time between the time it sets the ULP request in register and the time the D-PHY is disabled – this ensures that the ULP request is detected on the D-PHY interface.