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TDA2SX: HDMI display is not coming & HDMI source detect is also not happening

Alapati kavyaharini
Expert 1080 points
Part Number: TDA2SX
Other Parts Discussed in Thread: TPD12S521

Hi all,

I am working on custom board,the ESD protection chip (TPD12S521DBTR) is there in our custom board.

When I'm running the apps.out with null source display atleast the HDMI source is also not detected at TV monitor,It is always showing No signal.

I added some debug prints to know the problem in custom board.

what ever the protection ESD chip we are using that is same in D3 also,we have D3 board with us so I added the same print messages in D3 apps.out code and compared with my logs.Both logs are same

1. I made one test scenario,the custom board apps.out and the supporting lib_firmwares I copied in to D3 sdcard and tested in D3,at that time my apps.out is working fine display is coming.

2. with same apps.out I tested in custom board display is not coming.

3. I observed the voltage differences between the D3 board and Custom board at HDMI_HPD pin

In D3 board: without HDMI: 0V is coming(at pin #19 and 20 of TPD12S521 chip)

with HDMI : around 3.3v at #19pin and 5v at #20 pin

In Custom Board: Without HDMI : 1.8v is coming(at pin #19 and 20 of TPD12S521 chip)

with HDMI : around 3.3v at #19pin and 5v at #20 pin

Is this voltage 1.8v creates any problem in detection of HDMI.Because same code is working in D3 but not in custom board

Please suggest me to debug or identify the issue.

Please help me to solve this issue.Because it is very crucial stage to my project now.we are awaiting of HDMI display.Thanks in advance.

  • 0
    TI__Genius 12455 points

    Hi Alapati,

    Have you ensured the ESD routing is same as in D3 board. The PIN 19 & 20 are for HPD and they should not be at 1.8V

    Please speak to board-design engineer and ensure the ESD design/routing is same as in D3 board.

    Regards, Sujith

  • 0 in reply to Sujith
    Expert 1080 points

    Hi Sujith,

    Thanks for the reply.

    I will speak with my designer about the design/routing of the ESD chip.

    In the mean while,Could you please tell me Is there anyway to debug this issue from software side? I want to know exacly which register specifies/determining the detection of HDMI.

    Could you please explain me,How this 1.8v effects/creates the problem in detection of HDMI & display?So that I can analyze the issue in-depth and this information will also be useful to our hardware team.

    Thanks & Regards,

    A.Kavya Harini

  • 0 in reply to Alapati kavyaharini
    Expert 1080 points

    Hi sujith,

    Waiting for your Reply.

    1. I have taken the register dump of HDMI_WP registers with HDMI and Without HDMI in our custom board as well as D3 board.I observed two register values are different among all the HDMI_WP registers,when compared with D3 register dump.

    a) In custom Board, With out HDMI

    at addr: 0x5804 0024 =  0x26010010 (This register name is not mentioned in TRM it is reserved register)

     HDMI_WP_PWR_CTRL(addr:0x5804 0040)  = 0x9A

    b) In custom Board, with HDMI

    at addr: 0x5804 0024 =  0x26010010 (This register name is not mentioned in TRM it is reserved register)

     HDMI_WP_PWR_CTRL(addr:0x5804 0040)  = 0x9A

    c) In D3 Board,with out HDMI

    at addr: 0x5804 0024 =  0x26010010 (This register name is not mentioned in TRM it is reserved register)

     HDMI_WP_PWR_CTRL(addr:0x5804 0040)  = 0x9A

    d) In D3 board,With HDMI

    at addr: 0x5804 0024 = 0x22010010 (This register name is not mentioned in TRM it is reserved register)

     HDMI_WP_PWR_CTRL(addr:0x5804 0040)  = 0xAA

    Could you please tell me what exactly this Register dump means,because in TRM datasheet those bits and registers are in reserved.

    Please Help me to analyse the exact issue.

    2. I have a doubt,the ESD chip used in D3 board and in our custom Board are same that means the routings are also need to be same as in D3? Routings are different from Board to Board? Am I right.

    Thanks,

    A.Kavya Harini.

  • 0 in reply to Alapati kavyaharini
    TI__Genius 12455 points

    Hi Kavya,

    On #1, Yes, this is reserved registers and typically the driver will not use reserved register to program the peripheral. The values in this are to be treated as read-only. Are you seeing that the driver is programming this register?

    On #2, Typically the routing would be same. Unless a functionality is being added/modified/deleted.

    On 1.8v on HPD line, by default this should be low. Once a sink is connected/goes active this would go high/toggle. My concern is, since this is to be driven by the sink and with no sink connected who is driving this line. Are there other any signal routing issues? 

    Regards, Sujith

  • 0 in reply to Sujith
    Expert 1080 points

    Hi Sujith,

    One main thing is we are displaying & HDMI part everything is from M4 side not from A15 side.

    -->The values in this are to be treated as read-only. Are you seeing that the driver is programming this register?

    For this register addr: 0x5804 0024 I haven't seen any write/programming in the driver.

    For HDMI_WP_PWR_CTRL,I observed some code in this function "halHdmiWpSetPhyPwr" at path "ti_components/drivers/pdk_01_10_00_08/packages/ti/drv/vps/src/vpslib/hal/src/vpshal_dssHdmi.c".May be in this code it is setting the power state and reading the status of that & waiting for connection of HDMI.Am I right?

    This HDMI_WP_PWR_CTRL[3:2] bits have Read and write access and remaining bits are Readonly.

    Could you please tell me what exactly the register dump(what I posted earlier) is telling about detection.

    ---> Are there other any signal routing issues?

    The Hardware team is checking on the routings,if anything they update me I'll tell u.

    Thanks,

    A.Kavya Harini

  • 0 in reply to Alapati kavyaharini
    Expert 1080 points

    Hi sujith,

    Waiting for your reply.

    I observed these values of  in the Working board,D3

    a) HDMI_WP_PWR_CTRL = 9A without HDMI

        HDMI_WP_PWR_CTRL = AA with HDMI

    b) at addr: 0x5804 0024 =  0x26010010 without HDMI

        at addr: 0x5804 0024 = 0x22010010 with HDMI

    In custom board it is always showing a) HDMI_WP_PWR_CTRL = 9A with & without HDMI b) at addr: 0x5804 0024 =  0x26010010 with & without HDMI

    what exactly these registers are saying because in TRM datasheet also those are reserved bits & reserved register.I want to know exactly what does these register values mean?

    Please help me.

    Thanks,

    A.Kavya Harini

  • 0 in reply to Alapati kavyaharini
    TI__Genius 12455 points

    Hi Kavya,

    I don't have much information on the reserved registers. But the important thing would be the 1.8v on HPD. Please ensure the HPD signal 0 when no sink is connected and is 3.3 when sink is connected.

    Regards, Sujith