TMDS171: I2c read/write issue - TMDS181

Hi,

I use TMDS171 between HDMI connector and FPGA.

The problem is that FPGA can capture 720P60 vedio data successfully,but cannot capture 1080P60 vedio data,the 1080P60 data capatred is incorrectly.

The i2c read/write issue  has been resolved ,and the configure is shown as below.but the problem remains

 <i2c_bitrate khz="100"/>

======No Lane Swap

======No Polarity Swap

======Signal detect disabled

======Power down disabled

======HPD Automatic power down enabled

======Local I2C data rate 100k

*/

write_TMDS171(0x09,0x02);//

/*

======Tx impedance 150 to 300 ohms

======DDC data rate 100k

======

======

*/

write_TMDS171(0x0B,0x08);//150~300

//write_TMDS171(0x0B,0x00);//no terminal

/*

======Vswing DATA defined by Rvsadj

======Vswing CLK defined by DataRate

======2dB de-emphasis

*/

//write_TMDS171(0x0C,0x01);//Vswing DATA defined by Rvsadj;Vswing CLK defined by DataRate;pre-emphasis:2dB

write_TMDS171(0x0C,0x6D);//VSWING_DATA Increase by 18;VSWING_CLK Increase by 18%;pre-emphasis:2dB

/*

======Data Lane EQ 6.5dB

======Clock Lane EQ 3dB

======

*/

//write_TMDS171(0x0D,0x15);//6.5dB 3dB

//write_TMDS171(0x0D,0x25);//10.5dB 3dB

write_TMDS171(0x0D,0x3A);//16.5dB 3dB

/*

======Sink application

======HPD_SNK gate enable

======Fixed EQ

======EQ Enabled

======Apply RxTx changes(Asser this at the end)

======Automatic redriver to retimer crossover at 1.0 Gbps

*/

//write_TMDS171(0x0A,0x95);//Automatic redriver to retimer crossover at 1.0 Gbps

write_TMDS171(0x0A,0x94);//fixed redriver mode

//write_TMDS171(0x0A,0x97);//fixed retimer mode

//toggle PD_EN bit

write_TMDS171(0x09,0x5);//enter Power down mode

//read_TMDS171(0x00);

write_TMDS171(0x09,0x02);//exit Power down mode

//read_TMDS171(0x00);

while(1)

{

read_TMDS171(0x00);

cnt++;

}

Hi,JMMN

write_TMDS171(0x0B,0x08);//150~300

write_TMDS171(0x0C,0x01);//Vswing DATA defined by Rvsadj;Vswing CLK defined by DataRate;pre-emphasis:2dB

write_TMDS171(0x0D,0x35);//14dB 3dB

write_TMDS171(0x0A,0xB5);//Automatic redriver to retimer crossover at 1.0 Gbps;Adaptive EQ

write_TMDS171(0x09,0xA);//enter Power down mode

write_TMDS171(0x09,0x02);//exit Power down mode

the reg value is shown below:

reg0x09:0x02

reg0x0A:0xB1

reg0x0B:0x08

reg0x0C:0x01

reg0x0D:0x35

Thanks!

Hi
I removed TMDS171 from one board，and I connected the input pins and the corresponding output pins with jumper，then FPGA can capture the 1080P60 data

I changed to pinstrap mode：
I2C_EN/PIN：L
SIG_EN：NC
VSadj：6.98K to GND
TX_TERM_CTL：NC
SWAP/POL：NC

and I tried to change the state of EQ_SEL & PRE_SEL：
EQ_SEL PRE_SEL
NC NC
NC L
H NC
H L
L NC
L L
but the issue remained in the above 6 situations

Hi,JMMN 

Thank you for your help

/*********************about FPGA input****************************/ 

My board was designed refered to Digilent Genesys video FPGA(Xilinx,XC7K325T)  EVM board.

The Digilent Genesys EVM board uses TMDS141 between FPGA and HDMI input connector,DC coupled,just as my case.

Since TMDS141 has a limited working temperature,I choose TMDS171,and the FPGA I used was the same as the Digilent Genesys EVM board.

  /******************* about EQ mode******************************/

Both the fixed EQ mode and adaptive EQ mode had been tested,the problem remained the same

 /*********************about RXTX apply****************************/ 

RXTX changing was applied by writing 0xB5 or 0x95 to reg0A

I measured the waveform of input and output lane of the TMDS171,pinstrap mode

1)EQ_SEL:NC(Adaptive EQ)

2)PRE_SEL:NC(0dB)

3)TX_TERM_CTL:NC(Auto select)

The waveform of the input lane2 is shown as below

The waveform of the output lane2 is shown as below

There seemed to be much signal distortion issues about the output lane2 waveform,so I checked the PCB layout ,but I didn’t find any doubts.

I change it to IIC mode, and I tried almost all configurations,I found that the waveform would be a little better if PRE_SEL was set to -2dB,and the TX_TERM_CTL was set to 150Ω~300Ω,but still be bad

I measured the output of TMDS141 on the Digilent Genesys EVM board,the waveform is shown as below

clock

data lane

It seems to have the same problem as my board,I found that FPGA can't capture 1080P video neither on the Genesys EVM board occasionally. 

Eyescan Tool cannot find any TI's Interface

TP240141 is connected to the computer,and the USB driver is installed already, TP240141 is recognized by Windows system.

if I use Control Center software designed by Total Phase,the register can be read successfully.

I was totally confused...

The eye scan tool interfaces through USB to the I2C bus using a TUSB3410 (available on the TMDS181/171 EVMs), without a TUSB3410 the tool does not work.

You can pull the register data using Total Phase Aardvark.

Regards,

JMMN

Page0 and Page 1 register of TMDS171 cannot be read by TP240141 mentioned on SLLU217A,just bacause TP240141 does't use TUSB3410

so if I want to read the Page0 and Page1 register of TMDS171 on my board,I have to use TMDS171 EVM,and the I2C address of EMV board must be different from the board designed by myself.

Is that correct?

Hi JMMN

I readback regB0h and regB1h of Page1,but I'm not sure the operation is correct or not

write_TMDS171(0xFF,0x01);//Page1

read_TMDS171(0x00);//read

the value is shown as below

reg0xB0:0x5E

reg0xB1:0x88

Hi,JMMN

I changed TMDS171 to TMDS181,and I force it to redriver mode,the other configuration is shown as below

PRE_SEL：5dB

TX_TERM:75~150

AEQ

Data swing increse 24%

CLK swing increse 16%

it works well,FPGA can capture 1080P60 data successfully.

since I use a camera and splitter, so I change to the second port of the splitter,this time it does't work.

I connect camera directly,it does't work neither

I find another configuration for "second port" and "camera directly" situation,it seems to be better,but it does't work in "first port" situation

A few recommendations: tx terms of 75 to 150 are only used for 6G operation, you should use 150 to 300 ohms. 5 dB of de-emphasis is not recommended I would use 2 dB. Are the swing increases required to be very high? Typically, we would only use that high of a swing if driving a 10M + cable. Otherwise you may be overdriving the sink.

If you swap to retime mode, you can use eye scan to see how clean the signal coming into the TMDS181 / 171 is.

Regards,
JMMN