SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
The command operation can request a read or an acknowledge response from the panel after a long sequence of packets is sent. The Bus turnaround is also used to control the Tearing Effect control.
When a Bus Turnaround is requested from the command stream manager, the DPHY will be given a turn request. The request will make the DPHY interface perform a sequence of LP states (LP11-10-00-10-00) to indicate that it is releasing control of the DP/DN signals. The DPHY Direction signal will change once it detects the Panel side driving the LP00-10-11 states. The panel will then be able to send any response packets (see section 0) and release the bus by issuing a bus turnaround sequence to the controller DPHY. The DSITX controller DPHY will detect the sequence and change the direction signal once the pattern is sent and LP00 state is valid for 2-3 TX_ESC_CLK cycles.
Figure 12-385 shows Bus turnaround timing sequence from controller to panel and panel to controller.