[GSoC Weekly Overview]: Days of slient hardwork

Lets first start with some good news. After all I’ve plenty of bad news this week!

Integration with HDMI2USB Core

After frustrated with repeated failure of all my tests, I decided to try something new (& adventurous maybe?). I decided to integrate whatever code and working system I had up till now into the HDMI2USB Core. Actually, Jahanzeb already had incorporated most of the VGA code already in it in comments. So, my job got easier!
I can say that the integration went fine as I was able to switch to VGA source using the “Right Button” of Atlys. But, obviously due to imperfect capturing, the output of mplayer through USB, was coming out garbled, but I could atleast deduce that it was actually the garbled output of VGA. I could observe color bars from my test pattern. HDMI output, though, was blank.
[Pic: ToDo: Screenshot of mplayer’s output here?]

Good progress with VGA capturing from test source

I was able to reduce flickering from the VGA capture output. The VGA source used was a FPGA board running Jahanzeb’s test pattern generator code with my patch for alternating color bars. The source for flickering (of Type1, more details later) was the Auto-Offset Update Frequency register. The datasheet’s recommended value itself was giving flickering, but setting the update frequency to 3 VSYNCs seemed to work like magic! And, all this while I was thinking that my  VHDL code was incorrect! (But, hey wait for bad news!)
[Video: TODO Add Video here]

Time for negatives

After some success with test source using FPGA, I decided to try capturing of PC’s output. To my horror, there was a new issue of different type of flickering. That of screen blanking intermittently. Clearly, this AD9984A data related issue, it was more of SYNCs or DATACK issue. I’ll have to do more test and research on this one.

And, all the above text relate last 3-4 days only! So, what I was doing before that, you may ask! Some new things, like trying the Exar Linux drivers and resolving its issues. And, some regular things like code cleanup, repository restructuring etc. Rest time was spent testing various options for reducing flickering (that before that success mentioned above). Thats why the title “Silent hard work”. Its very uncomforting that you try and try things and each one fail, so you have nothing good/exciting to announce. But, projects do have these phases. So, I’ve to give more effort and be focussed.
For more technical oriented viewers, please have a look at the daily logs. If you have any solution/suggestion in mind, kindly do not hesitate to share. It would be very helpful.

Upcoming Week:

This is crucial section. I want to mention some things. First, its 1 month over since I started working from 29th. And second, I have 5-6 weeks only remaining, and these are very crucial for timely and successful completion of project. This require more effort and careful planning.
First, lets see what things are remaining in decreasing of importance(priority):
  • Perfect Capturing from VGA. Time Required: Unpredictable. Hopefully 1 week more.
  • PCB version 2 designing, fabrication, assembly and testing. Time Required: Will require about 6-7 days for designing(including review by mentors and community), 1 week for fabrication(in meantime, I could do other remaining works), and 1-2 days for assembly and finally 1 day for testing if all goes well.
  • I2C Integration into VHDL. Right now I’ve to do many changes to register configuration on-the-fly so I’m using BeagleBone Black for quick prototyping. But, obviously I’ve to integrate I2C into VHDL. Time Required: Will require a day or at-most 2 days.
  • PCB version 3, if version 2 doesn’t come up well. But, there is very less chance of that. I’ll try to ensure version-2 atleast becomes pre-production standard.
  • Any remaining things like documentation, feature implementation on HDMI2USB like auto-detection etc.

So, rather than deciding before hand, I need some discussion with mentor on how to proceed. Should I aim for perfect capture and then move onto PCB, or should I design the PCB and send it for fabrication, in meantime working on correcting the capture while the PCB returns from fab. Uncertain on these things. I’ll have to discuss this with my mentor.

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