MIPI-DSI to LVDS Bridge

Technical Support
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Hi there,

We are currently in the process of designing our custom carrier board. We will connect our custom display using LVDS. Toradex suggested to copy paste the design used for the Verdin MIPI-DSI/LVDS adapter.

Our hardware and software consists of:

  • Verdin iMX8M Plus
  • Custom carrier board
  • Torizon OS + Torizon Cloud
  1. The Toradex-Design uses the QFP variant of the SN65DSI84 bridge. This specific part is currently not available. However the bridge is available in a BGA version. Is there any particular reason not to use the BGA package instead QFP?
  2. The Toradex-Design incorporates an EEPROM on the adpater. As far we understand this EEPROM is used in some cases to identify the adapter in the bootloader to apply the correct DTO. Is it correct to assume we will not need this EEPROM as everything will be assembled on our board and we will know in advance what DTO to add to our image?
  3. The bridge in the Toradex-Design is connected to I2C_1 (according to the Verdin familiy spec.) even though the family spec. defines I2C_2 as the interface to be used for DSI bridges. Should we just use I2C_1 as well or actually use I2C_2 for the bridge even though we would have to configure the bridge accordingly in the device tree?

Thanks in advance,
Philipp

2

Greetings @p.stucki.dp,

The Toradex-Design uses the QFP variant of the SN65DSI84 bridge. This specific part is currently not available. However the bridge is available in a BGA version. Is there any particular reason not to use the BGA package instead QFP?

I’m not aware of any issues here, though I’m not entirely sure. I’ll double-check with our hardware team to be sure.

The Toradex-Design incorporates an EEPROM on the adpater. As far we understand this EEPROM is used in some cases to identify the adapter in the bootloader to apply the correct DTO. Is it correct to assume we will not need this EEPROM as everything will be assembled on our board and we will know in advance what DTO to add to our image?

Your intuition is correct on this. In fact if you check the DSI to LVDS schematic example we provide in our Verdin Carrier board design guide. We don’t even have an EEPROM in the schematic example.

The bridge in the Toradex-Design is connected to I2C_1 (according to the Verdin familiy spec.) even though the family spec. defines I2C_2 as the interface to be used for DSI bridges. Should we just use I2C_1 as well or actually use I2C_2 for the bridge even though we would have to configure the bridge accordingly in the device tree?

Again referencing the schematic example in our design guide I see we use I2C_1 in the example and I2C_2 is actually shown as not connected to anything. I would stick with the example we provide unless you have legitimate reason to deviate from this.

Best Regards,
Jeremias

1 Like
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Hi Jeremias,

Thanks for your reply.

I’m not aware of any issues here, though I’m not entirely sure. I’ll double-check with our hardware team to be sure.

Thanks for checking.

Your intuition is correct on this. In fact if you check the DSI to LVDS schematic example we provide in our Verdin Carrier board design guide.

Thanks to pointing to the reference schematic in the family spec. We were focused on looking at the schematic used for the adapter. The reference schematic has everything in one picture.

Again referencing the schematic example in our design guide I see we use I2C_1 in the example and I2C_2 is actually shown as not connected to anything. I would stick with the example we provide unless you have legitimate reason to deviate from this.

We will stick to I2C_1 then.

Best Regards,
Philipp

4

Regarding the BGA packaging. I checked with my team and they said there should be no major issues as it’s purely a physical/mechanical design difference. One additional thing that might matter is that there is a difference in temperature range in case that matters for you: Compare products

Best Regards,
Jeremias

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Thanks for checking back. We will use the BGA packaging then. We have already noted the difference in supported temperature range.

Thanks,
Philipp

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Glad I was able to help!