AM62L-PROCESSOR-SDK: MIPI-DSI Display Not Rendering GUI – Possible DSS Data Bus Width Mismatch (24-bit vs 18-bit)

This thread has been assigned to the concerned expert, please expect a response within 2 days.

Hello Dheeraj,

Please refer to the pin mapping for 18-bit.

If you are using 24-bit i suspect you may have to use the MSB 6 bits.

I need a PDF searchable schematics to review the connections.

Dheeraj K said:

My confusion arises from the usage of the DSS (Display SubSystem) configuration in the current setup. The DTS (device tree source) includes definitions for both DSS ports and the DSS driver. In the k3-am62l-evm.dts reference, 24-bit DSS output is configured in the pin control settings. However, our custom board supports only 18-bit RGB signals routed from DSS.

Divyansh, is there a 18-bit configuration support in the software that can be used.

regards,

Sreenivasa

 Hello Dheeraj,

We have a FAQ that lists all the key collaterals including the data sheet and TRM for customer to use.

Please refer below:

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1478018/faq-am62l-am62l32-am62l31-custom-board-hardware-design-collaterals-to-get-started

Regards,

Sreenivasa

Hello Dheeraj,

I assume you understand AM62L supports interfacing to Either DPI or DSI during run time.

The required display is expected to be configured during boot.

Regards,

Sreenivasa

Hello Srinivas, 

The AM62L processor supports interfacing with either DPI or DSI displays at runtime. In my setup, I have configured only the DSI display.

While I have successfully validated an RGB display using 18-bit color depth, my current focus is on a DSI display that uses 4 data lanes and requires 24bpp (bits per pixel) to render the GUI.

Given that the DSI display operates with 24bpp, I would like to clarify whether it is necessary to configure the pinctrl settings under the DSS node to use 24-bit data lines. Is there any direct relationship between DSS pin configurations and DPI signals in this case?

As I understand, for the MIPI DSI display to function correctly, both the DSS and DSI controllers need to be properly configured. I would appreciate confirmation on whether DSS pinctrl settings are still relevant when only the DSI interface is used.

Hello Dheeraj,

Please refer to the below section of the TRM

12.7 Display Subsystem and Peripherals
12.7.1 DSS
This section describes the DSS in the device.
12.7.1.1 DSS Overview
DSS is a flexible single-pipeline display sub-system that supports single high resolution display outputs. Input
pipeline supports gamma correction and brightness/contrast hue/saturation control capabilities for enhanced
video output quality. Each display output seamlessly connects to the DSI or OpenLDI display interface.
Optionally, it can drive other display interface controller type at the SoC level or connect to the device pins
as a parallel video output interface.

Expert input:

DSS pinctrl settings are not relevant since same DPI signals feed in to DSI Tx

Regards,

Sreenivasa