SN65DSI84 DSI-to-LVDS Bridge – Is External EEPROM Required for Configuration?

Technical Support
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Hi everyone,

We are using a Toradex SoM with a DSI-to-LVDS converter (SN65DSI84) to drive an LVDS display.

On our board, an EEPROM is connected on the I²C bus along with the SN65DSI84. We would like to clarify whether this EEPROM is mandatory for the operation of the SN65DSI84, or if it is optional.

Specifically, we want to understand:

  1. Is an external EEPROM required for:

    • Initial configuration of SN65DSI84?

    • Loading register settings at boot?

    • Any runtime read/write operation?

  2. If EEPROM is not used, can the SN65DSI84 be fully configured only via I²C from the processor / driver?

Current issue we are facing:

  • We are getting an error indicating “No HS/DSI signal detected”

  • On the DSI side, no clock signal is observed

  • As a result, there is no LVDS output

  • We are unsure whether this issue is related to:

    • Missing EEPROM configuration

    • Incorrect DSI host configuration

    • SN65DSI84 not being initialized properly

At the moment, we are stuck and would appreciate any clarification or guidance from someone who has worked with SN65DSI84 or a similar DSI-to-LVDS setup.

Any insights would be very helpful.
Thanks in advance!

2

Hi, I’m the Toradex AI Assistant.

I might make mistakes or occasionally get you wrong. Our support team will step in if needed.

I’d be glad to help clarify the DSI-to-LVDS setup! To provide the most accurate guidance, could you let me know:

  • Which specific Toradex SoM you’re using?
  • Which OS and version you’re running?

You can get this information by running the tdx-info command on your device. For more details, see: https://developer.toradex.com/software/development-resources/tdx-info/

Regarding Your EEPROM Question

Based on the Toradex DSI to LVDS Adapter documentation, I can provide some insights about the adapter’s I2C configuration:

I2C Interface Details

The Toradex DSI to LVDS Adapter uses a Texas Instruments MIPI DSI to dual-link LVDS bridge(1). The adapter includes I2C connectivity through multiple connectors:

  • LVDS Connector (X2) includes I2C signals: I2C_1_LVDS_SDA and I2C_1_LVDS_SCL with 4.7k pull-up resistors to +3.3V(2)
  • Capacitive Touch Connector (X3) also provides I2C signals: I2C_1_CTI_SDA and I2C_1_CTI_SCL with 4.7k pull-up resistors to +3.3V(2)

Compatible Hardware

The adapter is compatible with several Toradex modules including:

  • Verdin iMX8M Mini(1)
  • Verdin iMX8M Plus(1)
  • Verdin Development Board(1)
  • Dahlia Carrier Board(1)

Troubleshooting Your Current Issue

For your “No HS/DSI signal detected” issue, you might want to check if your setup matches the supported configurations. The adapter requires no external power supply(1) and connects directly to the MIPI DSI connector on Verdin carrier boards(1).

Once you provide your specific hardware and OS details, I can give you more targeted guidance for your DSI-to-LVDS configuration and help troubleshoot the missing clock signal issue.

Best regards, Toradex AI Assistant.

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