TFP410: No signal detected on the display

kenny peel

Prodigy 40 points

Part Number: TFP410

I have no signal displayed on the HDMI monitor that the TFP410 is plugged into.

I read some registers while the device was on:

CTL_1_MODE 0x08: 0x3f

CTL_2_MODE 0x09: 0x0d

CTL_3_MODE 0x0a: 0x00

DE_CTL 0x33: 0x02

H_RES 0x3a: 0x0672 (1650 pixels)

V_RES 0x3c: 0x02ed (749 pixels)

I'm using negative sync polarity and generating the timing with an FPGA.

The 5V pin on the HDMI plug is powered and the hotplug pin has 5V returning.

I'm sending a 74.25 MHz pixel clock to the TFP410.

Each bit D[23:0] is either tied high or low.

Here's a sample of my waveforms:

Do I have a configuration error?

Kenny

over 5 years ago

0 Brian Zhou over 5 years ago

TI__Guru*** 146695 points

ticket is assigned and will reply soon

0 Ikechukwu Anyiam over 5 years ago

TI__Mastermind 35130 points

Hi Kenny,

Are you providing a proper reset to the TFP410 on power-up (see section 7.4.4 of the datasheet)?

Regards,

I.K.

0 kenny peel over 5 years ago in reply to Ikechukwu Anyiam

Prodigy 40 points

I tried holding reset low during power up. It works with DVI but not HDMI. The screen flashes on and off with HDMI. I thought it could be an HDCP problem. I'm not doing anything with the DDC signal.

0 Ikechukwu Anyiam over 5 years ago in reply to kenny peel

TI__Mastermind 35130 points

Hi Kenny,

That's interesting. When you say the screen flashes on and off, is this a one time thing that happens on power-up or does it flash on/off indefinitely?

Regards,

I.K.

0 kenny peel over 5 years ago in reply to Ikechukwu Anyiam

Prodigy 40 points

It flashes on and off indefinitely with about a 2 second period when connected to HDMI. The screen is constantly on when using an HDMI do DVI converter cable.

0 Ikechukwu Anyiam over 5 years ago in reply to kenny peel

TI__Mastermind 35130 points

Do you see any differences in the the input and output signals when the flashing happens (i.e. any changes in HSYNC/VSYNC/DE and the input/output clock)?

Regards,

I.K.

0 kenny peel over 5 years ago in reply to Ikechukwu Anyiam

Prodigy 40 points

The signals from the FPGA to the TFP410 look the same when the screen is flashing with HDMI and when the screen is solid with DVI. The first scope shot is DOTCLK and HSYNC when the TFP410 is plugged into DVI. The second scope shot is DOTCLK and HSYNC when the TFP410 is plugged into HDMI. I did not monitor the TMDS signals coming out of the TFP410.

0 Ikechukwu Anyiam over 5 years ago in reply to kenny peel

TI__Mastermind 35130 points

It looks like there's a significant amount of noise coupled onto the HSYNC signal for HDMI. Is this also the case for VSYNC? That may be what's causing the flickering.

Regards,

I.K.

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TFP410: No signal detected on the display