I have implemented the SN65DSI83, SN65DSI84, and SN65DSI85 to bridge DSI video output from my processor to LVDS input on my display. However, the display is just blank and not showing any image. What could be the issue?
There are a number of steps you can take to debug this type of issue.
1. First, verify that you are following the initialization sequence listed in the datasheet. This sequence is critical for correct operation of these devices. Below is an example of what the initialization sequence should look like on an oscilloscope:
2. Verify that the video timing output from your processor matches what you are programming into the DSI83/DSI84/DSI85. This includes the DSI CLK frequency, active pixel data, and blanking pixel data. Video input timing, register configuration, and the panel timing requirements all have to match up for the video streaming to work without errors.
3. Make sure the LVDS timing parameters are within specification of the display panel datasheet.
4. Make sure the line time (time from HSYNC to HSYNC) on the DSI input matches the line time on the LVDS output. The line time on the LVDS output is the total amount of horizontal pixels divided by the LVDS clock frequency. You can measure the line time on the DSI input with an oscilloscope by zooming in on the data stream on of the data lanes like below:
The easiest way to configure these devices is to use the DSI-Tuner tool. You can reference these training videos to quickly understand how to use it for your application:
The DSI-Tuner will allow you to configure most of the device registers without having to look through the register map, and will provide feedback on whether or not the line time requirement has been met.
