DS90UB949-Q1: DS90UB949-Q1 EDID ?

Hi Kevin, 

Thank you for your question, I will take a look and get back to you by the end of the week. 

Best,

Shu

Hi Kevin, 

The internal EDID can be overwritten, please see this E2E thread for example script: https://e2e.ti.com/support/interface-group/interface/f/interface-forum/606928/ds90ub949-q1-how-to-change-the-edid-value. 

As for the external EEPROM, I am unable to see the schematic in close detail, can you attach it as a pdf? One thing I would like to check would be for the strap mode of the 949 to know that there is an external EDID. 

Best,

Shu

Hi Kevin, 

Based on the schematic hardware strap modes, the device is configured to check for remote EDID to be loaded. 

The 949 has several registers to be configured for remote EDID, the fields are described and listed in the datasheet. Below are the registers needed:

0x4F BRIDGE_CTL - EDID INIT may be set to reload EID SRAM

0x50 BRIDGE_STS - Status register, Read only

0x51 EDID_ID - make sure the I2C address of the EDID device is written to this register

0x52 and 0x53 are EDID_CFG registers to modify the hold times 

Can you share what these are set to?

Best,

Shu

Shu:

It seems that our hardware design needs to be modified. We need to set the mode to load the EDID of the local EEPROM. How can we modify our hardware?

How to set the register of synchronization 494?

The register information of initialization 494 is as follows:

Register 0X4F :  value 0X00

Register 0X50：value 0X97

Register 0X51：value 0XA1

Register 0X52:  value 0X1E

Register 0X53: value 0X00

Hi Kevin, 

In order to load from the internal SRAM, resistor R25 for MODE_SEL1 should be removed and adhere to the following mode strap setting. 

kevin.huang_FJXM said:

How to set the register of synchronization 494?

Can you clarify on this? I am not sure what synchronization is referring to. 

Best,

Shu

Shu:

      Q1 :How do I modify hardware to use external local EDID ?

      Q2: Please provide 949&948 initialization Settings.

      Q3: After we remove R25, the computer can recognize the EDID(external local EDID)  through HDMI, but 948 is unlock. Please help to analyze the problem

Hello Kevin,

kevin.huang_FJXM said:

  Q1 :How do I modify hardware to use external local EDID ?

To use external local EDID, strap MODE_SEL0 = #3 and set MODE_SEL1 = #1. Yu must also populate an EEPROM device attached to the DDC pins of the 949. The EEPROM must have the desired EDID loaded into it by some other external means. 

kevin.huang_FJXM said:

      Q2: Please provide 949&948 initialization Settings.

This is a very broad question. In general for basic video setup as long as you have mode strapped the device to the correct mode, and there is an EDID available to match your panel spec, then the process should be totally automatic to get display running

kevin.huang_FJXM said:

    Q3: After we remove R25, the computer can recognize the EDID(external local EDID)  through HDMI, but 948 is unlock. Please help to analyze the problem

MODE_SEL0 needs to be strapped to #3 for external local EDID mode. You can use pullup of 82.5k, and pull down of 102k for the MODE_SEL0 pin to set this. Also, what is the panel spec you are trying to drive? What resolution/PCLK? It looks from the EDID like 1920x1080. Is your HDMI source recognizing a 1920x1080 sink when you strap the modes correctly and plug the HDMI in?

Best Regards,

Casey 

kevin.huang_FJXM said:

    Q3: After we remove R25, the computer can recognize the EDID(external local EDID)  through HDMI, but 948 is unlock. Please help to analyze the problem

MODE_SEL0 needs to be strapped to #3 for external local EDID mode. You can use pullup of 82.5k, and pull down of 102k for the MODE_SEL0 pin to set this. Also, what is the panel spec you are trying to drive? What resolution/PCLK? It looks from the EDID like 1920x1080. Is your HDMI source recognizing a 1920x1080 sink when you strap the modes correctly and plug the HDMI in?

Q4:

MODE_SEL0 needs to be strapped to #3 :We use pull up of 82k, and pull down of 100k for the MODE_SEL0 pin to set this, and measurement voltage of VR4 is 0.983V.

MODE_SEL1 needs to be strapped to #1 : we remove R25.

The panel resolution is 1920 ×1080 and PCLK is 136.36 MHz（the EDID file is made by AWEDIDEditor.exe）

After setting the pin of MODE_SEL0/1 as you suggested, we find that 948 is unlock.

When we connect PC with 494 through HDMI cable, 498 is unable to communicate through I2C. (When we remove HDMI cable, 498 is able to communicate through I2C).

What do we need to do to solve 948 unlock & I2C communication?

Hi Kevin, 

Can you share the schematic on the 948 side?

Best,

Shu

Hi Kevin, 

Can you share the entire schematic? The above screenshot has elements cropped out. 

Best,

Shu

Shu

   Sorry, the PCB board of 948 is designed by the customer, so we can't get all the information. If you have any partly Settings that you want to confirm, we can try to get them.

Hi Kevin, 

I would like to check the MODE_SEL of the 948. Is it possible for you to get the register configurations for the 948? A register dump would be helpful in trying to figure out why the link is dropping. 

Best,

Shu

Shu:

     The register configuration is as follows on the 948 side

       Register 0x49 ,value 0x60.( Only this register is configured)

     The MODE_SEL of the 948 as follows(MODE_SEL0: Vmode=0V;   MODE_SEL1: Vmode=1.245V;). These are actually measured.

Hi Kevin, 

Making sure I understand the situation, when HDMI is connected, the link between the 949 and 948 drops? 

Are you able to use I2C to communicate with the 949 with the HDMI connected or is it just the 948 that is unable to communicate?

Can you share the value of register 0xC of the 949 before you connect the HDMI and after you connect the HDMI? 

Best,

Shu

hi Shu

We can use I2C to communicate with the 949 with the HDMI connected but the 948 is unable to communicate.

After HDMI connected  : register 0x0C ;  value :0x07

Before HDMI connector: register 0x0C ;  value :0x01

Hi Kevin, 

I will need some time to look into this, can you try to perform an HDMI reset by setting the 949 register 0x1 bit 4? Are you connecting the HDMI straight to the 949 after up and link to the 948 or have it connected prior to connecting to the 948? Can you share the power sequence? 

Also note that Monday 7/4 is a holiday in the US and responses may be delayed. 

Best,

Shu