TMDS181: TX Termination Control

Toshi

Part Number: TMDS181

Hi,TI,

About "TX Termination Control",

Under PIN mode, I can set the device as "Automatically selects the impedance" mode,

But Under I2C mode, I cannot set the device "Automatic mode" by "TX_TERM_CTL. Controls termination for HDMI TX. bit(Address : 0Bh[4:3],

Under I2C mode, if I don't know the signal rate, how to set the TX termiantion ?

Is it OK to set the termination a fix value(for example ) ?

over 8 years ago

0 Moises Garcia over 8 years ago

TI__Mastermind 23815 points

Hi Toshi,

Tx termination has to change from HDMI1.4 to HDMI2.0( data rate > 3.4Gbps), here you can monitor the value of register 0x0B[1] to set the proper Tx termination.

Regards

0 Toshi over 8 years ago in reply to Moises Garcia

Expert 1780 points

Moises, thanks.

I'd llike to confirm the following:

1. You said "......HDMI2.4 to HDMI2.0........",

Deos it typo ? "......HDMI1.4 to HDMI2.0........ "

2. User must change the termination value according to the HDMI version, correct ?

0 Moises Garcia over 8 years ago in reply to Toshi

TI__Mastermind 23815 points

Hi Toshi,

You are right, I had a typo, I'll fix it.
Yes, Tx termination has to change according to HDMI version.
For HDMI1.4 -> TMDS_CLOCK_RATIO_STATUS=0 (1/10)
For HDMI2.0 -> TMDS_CLOCK_RATIO_STATUS=1 (1/40)

Regards

Interface

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TMDS181: TX Termination Control