TDA4VM: Can DSS support BT.601 output to DPI interface?

Alex Lin Q

Part Number: TDA4VM

In TDA4VM TRM, it is declared that DISPC supports YUV422 output pixel format. But only BT.656/BT.1120 are specified.

We need BT.601 output over a 12-bit hardware interface. Can it be supported?

0 Yordan Kamenov over 5 years ago

Hi Alex,

for BT.601 support please check the following sections of the DRA829/TDA4VM/AM752x Technical Reference Manual (Rev. A):

12.6.2.1 DISPC Environment

12.6.2.1.4 VSYNC/HSYNC/DE Signal Export to SoC Boundary

Regards,

Yordan

0 Alex Lin Q over 5 years ago in reply to Yordan Kamenov

Hi Yordan,

Thanks for the information.

It seems that BT.601 can be supported with alternative VP1 output.

But here comes a question about the data pins.

As described in section 12.6.2.1.2, the bits [9-2] are effectively used in BT.656 mode (should be the same for BT.601).

The two LSBs are ignored. Then what HW pins should we connected to the external BT.601 display device (actually it's a serializer)?

Keep data[9-0] or just data[9-2]?

0 Brijesh Jadav over 5 years ago in reply to Alex Lin Q

Hi Alex,

If you require 8bit output, then use D[9:2] lines.

Rgds,

Brijesh

0 Yordan Kamenov over 5 years ago in reply to Brijesh Jadav

Hi Alex,

I have information from TRM team regarding your question:

data[9-2] pins should be connected. At DSS side, data[1-0] are always ‘0’ when BT.656 mode is selected.

Regards,

Yordan

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