DS90UB941AS-Q1: DGPIO1 can't transfer from des on link1 when in split mode.

chen zh

Part Number: DS90UB941AS-Q1

Hi TI:

We met one issue, please check below design, we use DGPIO1 for UB948 on link1. Interreupt report path is: DISPLAY(2) -> DGPIO1 on UB948(2)-> DGPIO1 on UB941 -> HOST.

We just found that DGPIO1 can't use when UB948 have only one link, Is there any configure way to solve this problem? We don't want to modify the hardware because of time. Thanks.

BRs，

Arvin

over 3 years ago

0 Aaron Heng over 3 years ago

TI__Mastermind 37040 points

Hi Arvin,

Thank you for reaching out to us. Your understanding is correct that the D_GPIO is required two links in order to transmit the information from the deserializer to serializer. May I know UB948 #1 and UB948 #2 are set to dual, independent, or single? Basically, it carried on LINK1 (PORT1) channel for D_GPIO signals. So, as long as you have both ports enable you should be able to transmit the signal.

Hope this helps. Let me know if you have further questions.

Aaron

0 chen zh over 3 years ago in reply to Aaron Heng

Intellectual 300 points

Hi Aaron,

Ub948 can only use one link in split mode. So I think ub948 should default to single mode.

Do you mean DGPIO is transferred by RIN1+/-, not by RIN0+/-?

BRs,

Arvin

0 Casey McCrea over 3 years ago in reply to chen zh

TI__Guru** 103215 points

Chen,

I think there was some misunderstanding here with Aaron's response. There is no way to map D_GPIO1 to work in single link mode for 948 so this needs to be resolved on the HW level.

The splitter mode GPIO functionality is described in this app note: https://www.ti.com/lit/an/snla308a/snla308a.pdf?ts=1639421296941&ref_url=https%253A%252F%252Fwww.google.com%252F

Best Regards,

Casey

0 chen zh over 3 years ago in reply to Casey McCrea

Intellectual 300 points

Hi Casey:

If UB948 is set to Dual link mode, then DGPIO1 in UB948 can work? Like below design:

If DGPIO1 still cannot be used, which scenario is this pin used for?

BRs,

Arvin

0 Aaron Heng over 3 years ago in reply to chen zh

TI__Mastermind 37040 points

Hi Arvin,

Yes. If you set the 948 #2 to dual, you can pass the data to the 941AS. If you have the EVM, you may also try this.

Aaron

0 chen zh over 3 years ago in reply to Aaron Heng

Intellectual 300 points

Hi Aaron,

I've not the EVM board.

1. Although i set the dual link in UB948, but we just connect port0 only, could DGPIO1 signal pass through port0?

2. Would it effect the display show in this situation: 1) use port0 only ; 2) set dual link

BRs,

Arvin

0 Aaron Heng over 3 years ago in reply to chen zh

TI__Mastermind 37040 points

Hi Arvin,

No. The D_GPIO1 can only configure via PORT1. I am not quite sure if I understood your second question.

Aaron

0 chen zh over 3 years ago in reply to Aaron Heng

Intellectual 300 points

Hi Aaron,

I don't know if you have looked this picture？ Let's confirm again...Thanks.

When 948#2 set dual link and use port0 only, will the following operations work normally??

1. Could DGPIO1 signal pass through port0 on 948#2(control signal)?

2. Do the display work normally(data signal)?

BRs,

Arvin

0 Aaron Heng over 3 years ago in reply to chen zh

TI__Mastermind 37040 points

Hi Arvin,

Could DGPIO1 signal pass through port0 on 948#2(control signal)? No. The D_GPIO can't pass the signal via PORT0. It is only worked on PORT1.
Do the display work normally(data signal)? Let me check on this.

Aaron

0 Aaron Heng over 3 years ago in reply to Aaron Heng

TI__Mastermind 37040 points

Hi Arvin,

Just to give you a quick updates that I am currently gathering all the hardware to try this on the bench to confirm my theory per our discussion. I will keep you posted by tomorrow.

Aaron

0 Hamzeh Jaradat over 3 years ago in reply to Aaron Heng

TI__Guru** 107710 points

Hello Arvin,

Can you please clarify whay do you want to configure 948#2 in Dual Mode but use Single Mode?

If you configure the device for Dual Mode without having any input, they will result in no LOCK for Port1, also errors will be reported. If your Controller is checking error status or LOCK status you will have issues. Also having both boards enabled will let the device expect half of the input to come from Port0 and the other half to come from Port1 which will lead to Display not working correctly!

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DS90UB941AS-Q1: DGPIO1 can't transfer from des on link1 when in split mode.