VSync detection issues after FW upgrade from 0.x to 1.X

[Louthrax]

Hi everyone,

After successfully resurrecting my OSSC (thanks to a great and quick help here), I decided in a craze of enthousiasm to upgrade it to the latest firmware (1.09).

I’m pretty sure my previous version of the firmware was 0.x (as my remote was inactive after the update and I had to set it up again). I then was unable to get any sync (using AV1_RGBS which was working pretty fine before). I saw in the forums here that some hardware changes were required to handle the new sync code.

I then downgraded to 1.08. Sync was back, but the detected video mode was wrong (something like 1000-p, instead of the expected 262-p from my MSX computer). HDMI display was fine though, but several output processing settings have no effects anymore (as the video source is not correctly identified I guess).

So I have the feeling that a hardware mod of some kind might be required between the 0.x and 1.x FW ? I could still be happy with the latest 0.x firmwares (if I downgrade to 0.x everything works again, I juste have to setup the remote again !), but maybe I’ll miss some new cool features ? Also, I like the new expanded OSD menus on 1.x 🙂

 

 

 

 

• This topic was modified 1 year, 4 months ago by Louthrax.
• This topic was modified 1 year, 4 months ago by Louthrax.

[Morpheus_79]

The hardware mod is absolutely necessary for every 1.x firmware, or else vsync detection does not work. I don’t know, why vsync is detected for you with v1.08 (maybe some old detection routines were still in place?)… but you HAVE to do the mod for all firmares starting with v1.x to work reliably.

It is possible to rewire the v1.6 pcb revision to work like the v1.8 revision (like i did here):

https://videogameperfection.com/forums/topic/ossc-v1-xx-series-beta-firmware/page/14/#post-59842

… but it’s harder to do, requires some microsoldering skills and is not that easy to undo.

[evileagleowl]

There is a regression related to vsync introduced in 1.09 fw. My MSX does not work properly with 1.09 while 1.08 is fine. I suppose that there may by more reports about that issue when more people upgrade to 1.09.

[wbahnassi]

Hi, I faced the same with my MSX as well. However, for me 1.08 didn’t work, and I had to go all back to 0.9. I did investigate what’s the reason and I think I know where the problem is. In 1.09, choosing Generic 4:3 on Line5x is causing the OSSC to choose timings for 960×288, whereas the previous firmware is choosing 1600x240L.  I think we need a fix to make Generic 4:3 Line5x choose 1600x240L again.

In the meantime, I managed to get back picture on Line5x on 1.09 by not using Generic 4:3, but 512×240 optim instead. Then I had to adjust timings for 512x240LB mode to the following values:

* H. sample rate = 684.0
* H. synclen = 50
* H. backporch = 51
* H. active = 570
* V. synclen = 3
* V. backporch = 41
* V. active = 240
* Sampling phase = 90 deg

Some of those values will vary for your monitor/TV, but the above works fine for me without needing any additional LPFs even. But yeah, I still prefer to go back to Generic 4:3 as that one worked fantastic without any tweaking.

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