RTOS/TDA2P-ACD: LCD - YUV output issue

Nevena Stojanovic

Part Number: TDA2P-ACD

Tool/software: TI-RTOS

Hi,

I'm trying to display YUV422 on LCD. Since, DSS does not support YUV422 output over discrete sync interface, refering to some posts on TI forum I found that the basic idea of how to get YUV422 is to "fool" DSS by saying that input YUV422 interleaved data is actually RGB565 and disable all pixel processing modules. I got YUV422 but the image is not 100% clear, it looks like it has "snow noise" on some colors.

DISPC_VID1_ATTRIBUTE (0x580010CC) register contains this value (0x8208880D)

Do you have some idea how to solve this?

Regards,

Nevena Stojanovic

over 6 years ago

0 Rishabh Garg over 6 years ago

TI__Guru 55685 points

Hi Nevena,

Can you check if www.ti.com/.../sprac23a.pdf helps you.

Regards,
Rishabh

0 Brijesh Jadav over 6 years ago

TI__Guru**** 476695 points

Hi Nevena,

Looking at the image, it looks like some bits are getting inverted.
What is your output interface size?
Atleast, colors are correct, so DSS is configured correctly.

Rgds,
Brijesh

0 Nevena Stojanovic over 6 years ago in reply to Brijesh Jadav

Intellectual 540 points

Hi.

The "snow noise" issue was related to some HW problem.
When I changed the board LCD3 works fine, but for LCD1 and LCD2 instances, colors are swapped (red/blue). When I enable two
pipelines for LCD1 or LCD2, the colors are in the right order.

I set DISPLAY_LINK_INST_DSS_VID2 for displayId in use-case:

if(pPrm_VideoLCD)
{
pPrm_VideoLCD->rtParams.tarWidth = displayWidthLCD;
pPrm_VideoLCD->rtParams.tarHeight = displayHeightLCD;
pPrm_VideoLCD->displayId = DISPLAY_LINK_INST_DSS_VID2;
}

In chains_common.c I enabled only one video pipeLine:

pVInfo->mode = 0;
pVInfo->isInputPipeConnected[0] = FALSE;
pVInfo->isInputPipeConnected[1] = TRUE;
pVInfo->isInputPipeConnected[2] = FALSE;
pVInfo->isInputPipeConnected[2] = FALSE;
pVInfo->isInputPipeConnected[3] = FALSE;
pVInfo->writeBackEnabledFlag = FALSE;

pipeOvlyPrms[1].pipeLine = SYSTEM_DSS_DISPC_PIPE_VID2;
pipeOvlyPrms[1].globalAlpha = 0xFF;
pipeOvlyPrms[1].preMultiplyAlpha = 0;
pipeOvlyPrms[1].zorderEnable = TRUE;
pipeOvlyPrms[1].zorder = SYSTEM_DSS_DISPC_ZORDER0;

status = System_linkControl(gChains_commonObj.displayCtrlLinkId,
DISPLAYCTRL_LINK_CMD_SET_OVLY_PIPELINE_PARAMS,
&gChains_commonObj.pipeParams[1],
sizeof(DisplayCtrlLink_OvlyPipeParams),
TRUE);

With this changes LCD3 works fine, but for LCD1 and LCD2 I got swapped colors.

VID2_ATTRIBUTES 0x5800115C = 0x4208880D
DISPC_CONFIG2 0x58001620 = 0xC00
DISPC_CONTROL2 0x58001238 = 0x129

After writing the same value 0x4208880D in VID1_ATTRIBUTES or VID3_ATTRIBUTES registers, then I got colors in right order.

Do you have any suggestions about this behavior?

Regards.

Nevena Stojanovic

0 Rishabh Garg over 6 years ago in reply to Nevena Stojanovic

TI__Guru 55685 points

Hi Nevena,

In the fail case what is the value of VID1_ATTRIBUTES or VID3_ATTRIBUTES register?

Regards,
Rishabh

0 Brijesh Jadav over 6 years ago in reply to Nevena Stojanovic

TI__Guru**** 476695 points

Hi Nevena,

Could you please first understand the problem that you are facing?
According to above LCD3 works fine, but LCD2 and LCD2 output does not.. But then you are saying, when two pipelines are enabled, color are right? How are there pipelines connected to LCD outputs ? Please note we cannot connect two pipelines to one LCD output..

Also i see LCD2 output is eanbled for 16bit, is that correct?

You will need to make sure the input format is RGB565 and output format set correctly as required for connected display..

Rgds,
Brijesh

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RTOS/TDA2P-ACD: LCD - YUV output issue