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msh
Voyager
Voyager
1,206 Views
Registered: ‎10-31-2016

Xilinx Gamma LUT IP : look up table update

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Hello, 

I try to use the IP from xilinx "Gamma LUT IP", where I load the Look up tabel via the address according to example.

base addrr + 0x800

base addrr + 0x1000

base addrr + 0x1800

This works, but I dont know which is for Red, green , blue channel or it is for 3 LUT. This address are I think  from old gamma correction IP from Xilinx which is uncontinued now.

Secondly, I would like to ask why in the gamma LUT datasheet (pg285) ithe LUT address for loading values is given base addrr + 0x0fff, base addrr + 0x17ff and base addrr + 0x1fff for three LUTs. 

This doesnt work !!!!

May I know how to code look up table and shift the look up table i..e 1,2 and 3 during run time 

thank you 
Kind regards 

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florentw
Moderator
Moderator
1,163 Views
Registered: ‎11-09-2015

HI @msh,

Thank you for reporting this,

You are correct the register space is incorrect in the documentation. We already noticed that and it will be fixed in the 2018.3 version of the documentation. The correct one are as you mentioned:

LUT0 is 0x800
LUT1 is 0x1000
LUT2 is 0x1800

For the mapping between LUT and colors, this is missing from the documentation. I reported this to development and they will correct the documentation. The detail is:

LUT0 is Red
LUT1 is Green
LUT2 is Blue

Hope that helps,


Florent
Product Application Engineer - Xilinx Technical Support EMEA
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5 Replies
florentw
Moderator
Moderator
1,164 Views
Registered: ‎11-09-2015

HI @msh,

Thank you for reporting this,

You are correct the register space is incorrect in the documentation. We already noticed that and it will be fixed in the 2018.3 version of the documentation. The correct one are as you mentioned:

LUT0 is 0x800
LUT1 is 0x1000
LUT2 is 0x1800

For the mapping between LUT and colors, this is missing from the documentation. I reported this to development and they will correct the documentation. The detail is:

LUT0 is Red
LUT1 is Green
LUT2 is Blue

Hope that helps,


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**

View solution in original post

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msh
Voyager
Voyager
1,160 Views
Registered: ‎10-31-2016

Is it possible to have double Look up table for RGB i.e. according to scenerio (during run time) I would like to change the LUT for gamma correction. 

eg: 

1st i work with 1 LUT  for all RGB 

then in 2nd I work with 2 LUT for all RGB ? 

 

Best regards

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florentw
Moderator
Moderator
1,121 Views
Registered: ‎11-09-2015

Hi @msh,

No I do not think this is possible. Each time you want to change the LUT, you might have the restart the IP to update the parameters.

Regards,


Florent
Product Application Engineer - Xilinx Technical Support EMEA
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rahul_gs
Observer
Observer
1,069 Views
Registered: ‎06-19-2018

Can you please tell how to load values into these registers?

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florentw
Moderator
Moderator
1,032 Views
Registered: ‎11-09-2015

Hi @rahul_gs,

This is a different question. Please create a new topic.

As this topic is already marked as solved, I am closing it for new replies

Thanks for your understanding,

Best Regards,


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**
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