i want to verify the DAC ADV7123KSTZ140. This DAC is connected to Xilinx FPGA V4. how to generate digital data to feed to this DAC for generating RGB PAL output?
Your question has been forwarded to the part specialist and you will get an update soon
As you know the ADV7123 is a video DAC. Takes in digital data on the input and output analogue currents on IOG/IOB/IOR output pins. The currents drive a connected load to develop voltage. Did the datasheet says it support PAL RGB anyway?
For what you want to achieve using this DAC might be very time consuming and a lot of work and might lead you no where, since you need to take into account the color burst information for PAL and how do you generate it from your FPGA and how to do decode this PAL output at the output of the ADV7123 device.
So we have encoder products such as the ADV7393 which will basically meet your design needs. Have you looked into that?
My board is designed and the DAC part is fixed by my client.
I need to prove the h/w by testing the video dac o/p.
All I want is to feed some digital data and check the o/p by connecting to Monitor or display.
Can I write some data from fpga to DAC and see the o/p?
I want the procedure to evaluate the DAC to prove my H/W.
I have attached a reference design circuit for the ADV7125 (8bit DAC) whereby the DAC is driven digitally and the o/p observed using a VGA connector that plugs to a monitor.
The ADV7123 is a 10bit DAC. So if you provide a known video data (internally generated test pattern from your FPGA) then you should see this on the monitor attached to the ADV7123. Does this help you?
I am asking for “how to generate a known video data inside FPGA to feed to DAC ADV7123”.
I have not found any attachment of reference design circuit which you have mentioned.
I have gone through AN-1180, Appendix A, Table 1. There are no built-in features for automated testing for ADV7123.
How to generate a known video data for this DAC to verify its output?
It is your initiative on how to generate your data output to provide to the DAC (ADV7123). Is ADI supposed to do that for you?.
have you read the data sheet for the device in question? It is a DAC that takes in digital data and clock and output analogue currents values that represent the digital inputs applied. For example for digital code all 1's, you would expect to get maximum current and for mid digital code, you would expect to get half current and for digital code all 0's you would expect to get minimum current.
The reference circuit can be seen by all tagged as ADV7125_png.PNG.
Thanks for your reply. I do know the basics of DAC which you have elaborately explained.
I am interested in knowing if some known Video data has been generated by ADI to test this particular DAC for any evaluation board.
You may close the case if there is no test case generated/used by ADI.
I will write some random data and check it.
In some of our video decoder products evaluation boards, which you would need to purchase anyway, might have the ADV7125 DAC onboard. We have in-built video data such that in the absence of input applied to the decoder, the decoder enters free run or you can force free run to a color bar test pattern. in free run mode the output of the decoder is output to ADV7125 DAC. So a connected monitor on the VGA port of the decoder evaluation board will show this color bar test pattern.
So for this DAC ADV7123, there is no free run capability.
I understood that there is no free run capability. i had already written earlier that i have gone through AN-1180, Appendix A, Table 1. in which it is mentioned that there are no built-in features for automated testing for ADV7123.
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