DS90UB954-Q1: When 0x7c register is configured 0xc0, split screen will appear, otherwise, black screen will appear

Hello,

Your assumption is correct, if you are using the 953 as the serializer then it should be operating in CSI mode and changing the 10-bit settings won't have any affect.  If there are errors occurring then that may cause issues like the ones seen above.  I would suggest looking at registers 0x4D and 0x4E to see if any errors are occurring on that port.  If errors are occurring then it may be necessary to verify that the channel meets the recommendations in the datasheet.  

Regards,

Nick

Hi Nick

1. in fact  ,if set the  0x7c (serializer  953 csi mode.),high probability occurrence split .

if do not set 0x7c，low probability occurrence split .but maybe have dark screen. means no output.

2. when split  read the value as follows

[0xdB  0x4d 0x4e]   data is  [0x7b, 0x33, 0xfd]

and 0x7A = 0xf

some advice？

thanks

Hello,

The registers that were pulled I am assuming that they match respectively like below:

0xDB: 0x7B,

0x4D: 0x33,

0x4E: 0xFD

But this shows that there are some errors in the link.  It may be worthwhile to run the MAP tool in Analog Launch PAD which is described here https://www.ti.com/lit/ug/snlu243/snlu243.pdf?ts=1591288007527.  

Also what are the settings you are using for the internally generated framesync?

Regards,

Nick

Hi Nick

from the link ，we will check the AEQ.

 the internally generated framesync do u mean register 0x18(FS_CTL)? 

do not set 0x18 ,use its default value.

How to configure it？

Thanks

By the way ,u are right, the data as below: 

0xDB: 0x7B,

0x4D: 0x33,

0x4E: 0xFD

0x7A : 0x0F

Okay sorry for the confusion, I saw the original question linked was regarding the internal frame sync generator.  If it is not being used then no need to configure it here.

Regards,

Nick

Hi Nick

ok，let us focus on the settings.

I test the setting again.

if set the  0x7c [c0] (serializer  953 csi mode.), first open , it must be split.

if do not set 0x7c，first open,it do not have split.

why?

 from  datasheet  can see on csi mode ,no matter whether 0x7 is set or not, it should not work.(means set or not ,do not affect the output)

in fact ,it affect the output on csi mode. why?

by the way ,if do not set 0x7c,low probability occurrence dark screen( means no output.)

thanks

Hello again,

I think I am confused here.  If you are not operating in 10-bit mode (operating in CSI-mode) then there is no reason to set those bits.  I am not sure of the effects setting these bits would have on CSI mode, I would think there would be no effect.  If you are operating in CSI mode with a 953 as the serializer then I would not set 0x7c.  Also are there any conclusions to be draw from the testing the link?

Regards,

Nick

HI Nick

 0x4D bit[0]  is 1 , do it  means the 954 receive the input data have no errors?

Hello,

No, so there can be lock with some errors, the term lock simply means that the device is able to lock onto the clock of the FPD-Link signal.  There may still be errors in the transmission and will typically set other error bits in register ox4D and 0x4E.

Regards,

Nick