DS90UB954-Q1: How to setting FV_MIN_TIME

Tomoaki Yoshida91

Genius 5255 points

Part Number: DS90UB954-Q1

Hi team,

Our customer is evaluating 953 on their system and 954 on EVM.

They are having trouble that the image can not be taken well.

When they set FV_MIN_TIME to 0, they can now capture video.

They made the settings by reading 7.4.14 Line Valid and Frame Valid Indicators in the data sheet.

How should FV_MIN_TIME be determined originally?

We do not know why FV_MIN_TIME is set to 0 and video can now be captured.

We need to understand the reason and how to set it correctly.

However, although the video can now be captured, the video is out of color and missing.

The trouble is still going on.

If you like, I send you the register settings locally so please check it.

Best regards,

Tomoaki Yoshida

over 6 years ago

0 Steven(Shenzhen) Shi over 6 years ago

TI__Mastermind 30515 points

Hi Yoshida,
pls refer to ub954 d/s page40 on LV/FV timing description, it is on the frame and line boundary at the 954 receiver. also table11 is defining the minimum FV to LV spec. in RAW mode. If FV_MIN_TIME is set as 0, it means the minimum FV/LV timing should have =3/5 PCLKs for RAW12F/10 respectively. if NOT correct, maybe the first line would be discarded.

regards,
Steven

0 Tomoaki Yoshida91 over 6 years ago in reply to Steven(Shenzhen) Shi

Genius 5255 points

Hi Junqiang-san,

Thank you for your support.
I am checking the data sheet.
However, I still do not understand enough.
If the sensor spec of FV to LV is mode is less than 4PCLK in RAW10 mode, does it mean that timing can not be adjusted?

Best regards,
Tomoaki Yoshida

0 Steven(Shenzhen) Shi over 6 years ago in reply to Tomoaki Yoshida91

TI__Mastermind 30515 points

Hi, Yoshida,
yes, it has minimum FV/LV request for camera system design. for this case, you can say the minimum FV/LV timing is 4PCLKs.

regards,
Steven

0 Tomoaki Yoshida91 over 6 years ago in reply to Steven(Shenzhen) Shi

Genius 5255 points

Hi Steven-san,

Thank you for your support.
In this case, how is the image from CSI-2 output.

In our situation, althougt FV_MIN_TIME is set as 0, the line seems to be off, and the image is closed by the left or right.

Best regards,
Tomoaki Yoshida

0 Steven(Shenzhen) Shi over 6 years ago in reply to Tomoaki Yoshida91

TI__Mastermind 30515 points

HI Yoshida,
The FV_MIN_TIME is used to set "Frame Valid Minimum Time". This register controls the minimum time the FrameValid (FV) should be active before the Raw mode FPD3 receiver generates a FrameStart packet.
If it is NOT met, the FS maybe is not correct.

regards,
Steven

0 Tomoaki Yoshida91 over 6 years ago in reply to Steven(Shenzhen) Shi

Genius 5255 points

Hi Steven-san,

Thank you for your support.

We seem to have to consider changing the sensor.
I understand that the setting of FV_MIN_TIEM is not necessary when connecting with 953.
Is this correct?

Best regards,
Tomoaki Yoshida

0 Tomoaki Yoshida91 over 6 years ago in reply to Tomoaki Yoshida91

Genius 5255 points

Hi Steven-san,

Thank you for your kindly support.

Any update on this issue?

We also started to study the camera module with 953.

I would like to confirm that the setting of FV_MIN_TIME is unnecessary, in 953-954 system.

Best regards,

Tomoaki Yoshida

0 Steven(Shenzhen) Shi over 6 years ago in reply to Tomoaki Yoshida91

TI__Mastermind 30515 points

Yoshida,
For the link between 913a and 954, why you need change the sensor? the FV/LV timing request in 954 is easily met.

regarding the link between 953 and954, yes, it has no FV/LV request.

best regards,
Steven

0 Tomoaki Yoshida91 over 6 years ago in reply to Steven(Shenzhen) Shi

Genius 5255 points

Hi Steven-san,

Thank you for your support.

The time between Vsync and Hsync of the camera used before is specified as 4pclk.

If this timing can not be adjusted to over 5PCLKs in some way, I think that it will be necessary to change to a camera with over 5PCLK or a camera using 953.

Best regards,

Tomoaki Yoshida

0 Steven(Shenzhen) Shi over 6 years ago in reply to Tomoaki Yoshida91

TI__Mastermind 30515 points

Yoshida-san,
For most sensors, the timing can be adjusted in some extends.
For 933/954 link the minimum FV/LV timing in RAW10 is 5pclk, pls secure to catch this need. thanks.

Best regards,
Steven

0 Tomoaki Yoshida91 over 6 years ago in reply to Steven(Shenzhen) Shi

Genius 5255 points

Hi Steven-san,

Thank you for your support.

Unfortunately, the FV_LV timing of the camera which we use is less than 4 PCLK and can not be changed.

However, we can capture the first line using this camera.

You mentioned earlier that the FS maybe is not correct.

Does this mean that the timing of FS may not be correct?

Or does it mean that the contents of FS data may not be correct?

Since the video can be captured as expected, I hope to use it as it is.

Best regards,

Tomoaki Yoshida

0 Tomoaki Yoshida91 over 6 years ago in reply to Tomoaki Yoshida91

Genius 5255 points

Hi Steven-san,

Any update on this issue?

We want to use the current environment for evaluation only, not within the scope of operation guarantee.

And our system just happens to be able to receive the signal at that timing.

If the first line can not be taken even if the timing is not good, I believe that it is possible to use the present system for evaluation only.

So, I would like to know what happens specifically if it does not meet the requirements of FV_LV.

Best regards,

Tomoaki Yoshida

0 Steven(Shenzhen) Shi over 6 years ago in reply to Tomoaki Yoshida91

TI__Mastermind 30515 points

Hello Yoshida-san,
regarding the FV/LV timing request, if it is not met, the first line would be lost. but it is NOT always all the first line is lost if the FV/LV timing is not met due to digital design.
For example, if you power-on/power off for more times, the mismatching timing of FV/LV would result into the 1st line loss. TI provided the safe design request in the d/s. if the FV/LV timing is met, it is designed and verified that the 1st line is NOT lost.

best regards,
Steven

Interface

Interface forum

DS90UB954-Q1: How to setting FV_MIN_TIME