1024p@50Hz and 960p@50Hz not displaying correctly

[awaken1ng]

Basically, this


1024p@50Hz is the only resolution that does this. Others are nice and crisp comparatively.

720p@50Hz for example


Curiously, 1024p@60Hz is fine. Tested on a couple of monitors (which outputs just like picture above) and a TV (which refused to output 1024p@50Hz due to "unsupported video mode").

Clock gen is installed, but I've tested GBSC for a bit prior to installing it, and it still did that. The board is GBS-8200 V4.0, dated 20231130.

The device is PS2, as could be guessed from the photos, connected with component cable. Display is connected with VGA cable. Running latest firmware at the time of writing (5293343b2c253a35e85cc5b638431cfaab3ed813).

Update: Found that 960p@50Hz is also affected, and cycling SDRAM in developer menu seemingly resolves the issue.

[awaken1ng]

Oh, I'm a dum-dum, for some reason thought cycling SDRAM was just, like, resetting the memory.

Setting SDRAM clock to 129 Mhz (according to debug output) specifically makes the problem go away, the higher clocks (144 Mhz and higher) starts showing a lot of "white dots noise" like the stock GBS did, and lower clocks is glitchy like the photo above.

Looks like PAL60 and NTSC seem to both run 129 Mhz in 1024/960p, and PAL50 doesn't, hence the glitchiness.

Presets seem to remember the SDRAM clock, so guess can just use that as a workaround for setting the 1024/960p resolution.

[ramapcsx2]

Hm, back when I coded the SDRAM section, all my GBS boards worked well with them, and I have a lot.. :p I suppose they still make them a bit different in the wild. Yours seems to not like some particular detail..

[Traeskie]

Oh, I'm a dum-dum, for some reason thought cycling SDRAM was just, like, resetting the memory.

Setting SDRAM clock to 129 Mhz (according to debug output) specifically makes the problem go away, the higher clocks (144 Mhz and higher) starts showing a lot of "white dots noise" like the stock GBS did, and lower clocks is glitchy like the photo above.

Looks like PAL60 and NTSC seem to both run 129 Mhz in 1024/960p, and PAL50 doesn't, hence the glitchiness.

Presets seem to remember the SDRAM clock, so guess can just use that as a workaround for setting the 1024/960p resolution.

Thanks for sharing this!

I have the same issue: Flickering dots with 50Hz 1024p/960p, other modes are fine. Tried with several different PSU:s up to 2A, no difference. Setting SDRAM to 129MHz fixes it, all other frequencies have similar issues. ...and I also assumed Cycle DRAM was some kind of reset :D

My board is GBS 8200 V4.0 20240417 and I've only tested with PS2 as input.