HD3SS215: SWITCHING LOGIC

penchala prasad

Part Number: HD3SS215

Hai,

can any one please tell what is the switching logic for switching port a to portc and portb to portc, and also vice-verse? i have refered below schematic and control logic even though i didn't get any output. i have used last two control logics as mentioned in the datasheet.

Thanks & regards,

prasad.hd3ss215_evm_c (1).pdf

over 6 years ago

0 David (ASIC) Liu over 6 years ago

TI__Guru**** 176571 points

Prasad

What is your input source and output sink? DP or HDMI?

Thanks
David

0 penchala prasad over 6 years ago in reply to David (ASIC) Liu

Intellectual 750 points

hdmi 1x2 rev 1.0_Schematic.pdfHai,

My input source and output sink are HDMI.

Thanks & Regards,
prasad.

0 David (ASIC) Liu over 6 years ago in reply to penchala prasad

TI__Guru**** 176571 points

Prasad

The schematic shows SCL/SDA from HDMI connector not being connected to AUX or DDC pin of HD3SS215? How do you plan the communication the HDMI DDC info?

What is the purpose of the BERG pin? These will degrade HDMI signal integrity.

Thanks
David

0 penchala prasad over 6 years ago in reply to David (ASIC) Liu

Intellectual 750 points

Hai David,

In schematic their is a connection from SCL/SDA from HDMI connector to AUX and DDC pins of HD3SS215. Please check once again.

As we are doing R&D on this for the first time we just kept berg pins for future use. If it creates a problem in signal integrity i will remove berg pins and short the path.

Thanks & Regards,

prasad.

4530.hdmi 1x2 rev 1.0_Schematic.pdf

0 David (ASIC) Liu over 6 years ago in reply to penchala prasad

TI__Guru**** 176571 points

Prasad

R4 and R6 show to be populated. But R23 and R74 being shown in the schematic as not populated, are they physically populated on the board?

Thanks
David

0 penchala prasad over 6 years ago in reply to David (ASIC) Liu

Intellectual 750 points

Hai David,

We have physically installed R23, R74, R36, R39 components and we have tried replacing zero ohm to 47k ohm their is no change, output is not displaying.

Thanks & Regards,

prasad.

0 David (ASIC) Liu over 6 years ago in reply to penchala prasad

TI__Guru**** 176571 points

Prasad

Please probe DA_HPD, DB_HPD, and DC_HPD first to make sure they are high when source and sink are attached.

If DA_HPD, DB_HPD, and DC_HPD are all high, please probe the DDC on DA, DB, and DC, and see if DDC is communicating between the source and sink.

Thanks
David

0 penchala prasad over 6 years ago in reply to David (ASIC) Liu

Intellectual 750 points

Hai David,

I have found some grounding issues i have resolved those. But the output is coming from port A to port C only even if i have the control logic input from port B to port C is not coming. can i know control logic to have 1x2 and 2x1 switching.

Thanks & Regards,

prasad.

0 David (ASIC) Liu over 6 years ago in reply to penchala prasad

TI__Guru**** 176571 points

Prasad

It is good that you got Port A to Port C to work. What is the setting of AUX_SEL and DX_SEL you are using? For Port B to Port C, you only need to change the DX_SEL pin setting. Please check DX_SEL and make sure it is properly high.

As part of the debugging, for HPD and DDC between Port B and C, you can bypass HD3SS215 and connect HPD/DDC directly between Port B and C. If display works, then we need to focus on the voltage of HPD and DDC communicaton. If display still does not work, then we need to focus on the main links.

Thanks
David

0 penchala prasad over 6 years ago in reply to David (ASIC) Liu

Intellectual 750 points

Hai David,

I have checked DX_SEL voltage level also.. I am using AUX_SEL at middle level and DX_SEL at two stages for port A and port B. As you suggested i have connected direct communication between HPD/DDC signals of Port B and C but their is not at the output.. but i am using a laptop as a input source for both Port A and B while connected Port B and C and input source indicating signal is going but at the monitor their is no display. What might be the issue?

Thanks & Regards,

prasad

0 David (ASIC) Liu over 6 years ago in reply to penchala prasad

TI__Guru**** 176571 points

Prasad

If DX_SEL voltage is correct, HPD is at 5V, DDC is communicating properly and you still don't see display, then you need to change signal quality on the main link, do you have a scope that you can verify the signal quality of the main HDMI link?

Since Port A to Port C is working, you can use it as a baseline and compare the result to Port B to Port C.

Thanks
David

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HD3SS215: SWITCHING LOGIC