Monitor recommendations for Chameleon

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  • Hi,


    What is the recommended specs for a LCD I should buy for my Chameleon. I want to find a suitable screen with VGA input

    so that when I hook it up to my Chameleon and watch demos, the scrollers and movements are without lag and jerky movements

    which is had on a cheap lcd-tv that was hooked up to a real c64 (svideo).


    Does the chameleon's native output thru vga take care of this for me so that things will run smooth on my tv or monitor (i will

    of course disable post-processing and set the screen into gaming mode).


    Tips ?

  • CHameleon supports a V-Sync mode that will give you just what you are looking for - if the monitor supports 50Hz and a variable number of lines per screen. The BenQ 50Hz office monitors (all 4:3) are surprisingly cheap and support this VGA mode.

  • Ok. Thanks for the BenQ tip. I will look into them on eBay. You say 50Hz -- does this mean that PAL TV screens should perform well and scroll smoothly since our TV sets in Norway are 50Hz ?

  • Yes, that's exactly what it means. However, only a few monitors really support the combination of 50Hz and V-Sync output. When we developed the feature, only CRTs were capable of displaying those modes, but now that more and more flat screens support it, we get lots of positive feedback for the smooth animation that the Chameleon produces.

  • I have long been thinking that all the fuzz on Amiga forums about sourcing 15kHz/50Hz capable monitors was pointless since normal LCD/LED TV screens would serve the purpose as they already were made for 50Hz appliances and to tolerate 15kHz input. However -- I have seen that they sample picture-data and display it with un-smooth result. But that might not be the case anymore ? I will try my Chameleon on VGA-input with the living room 55" Pioneer TV and see how it turns out :-) I guess it's a "trial and error" kind of situation :)

  • I have seen that they sample picture-data and display it with un-smooth result. But that might not be the case anymore ?

    Unfortunately, this is still the case. The picture is still "oversampled" by the internals of the monitor, which may lead to tearing or even jerky scrolling. For TVs, the situation may even be worse, as the VGA input is usually geared towards connecting "some standard PC". So although the TV is already made to accept a 50Hz signal on a different input, the plausibility check at the VGA input may be totally different.


    So yes, it's a trial-and-error thing.

  • I have the Benq BL702A (smaller version of the BL912 from the wiki) which supports the Amiga output and looks great. I'm very curious to see the output of the Chameleon V2 on this monitor.

  • espskog I've just received the Chameleon V2 and the VGA output looks very good on the Benq BL702A with scanlines enabled. Much nicer to look at than the already good s-video output of the C64 Reloaded MK-1 on an old Samsung SyncMaster 711MP. This is great because my old Commodore 1701 is making awful noises and I can't stand watching the flickering of old CRT displays anymore.


    I've made a picture but it is isn't too clear. It looks better in real life. And I think I can get an even nicer picture if I fiddle with the settings of the Benq somewhat. But I don't want to do that because it's setup for my Amiga. Now I'm afraid I'll want another Benq for the C64 as well...



  • Yes, that is very very nice. Oh I cannot wait till I get mine :) I think it's stuck somewhere in transit because it has said "Hamburg" for about 3-4 days or so now. Either there is a Hamburger sitting there playing with my TC64, or the mail man in ultra slow because we have about 100 meters of snow now ;)


    Thanks for sharing the info above. Looks super.

  • I found that 800x600, 50Hz and Vsync is the only viable option for my BenQ BL702A. This switches the monitor to 832x624 50Hz. When I enable scanlines 75% I get washed out colours. Probably to make it look like it did on a C64 on a CRT? Also, the scanlines are not perfect in vertical scrolling games. When the scanlines are off I get rich colours. Scanlines at 50 or 25% looks really bad at this resolution.


    640x480, 50Hz and Vsync makes the picture stretched too much vertically, making it wrong aspect ratio. I kinda wish there was a 640x512 and/or 720x576 option. The scanlines and aspect ratio would look better in these resolutions aswell.


    any plans to update this aspect of the Turbo Chameleon 64 V2?

  • I own a V1, but it would be really nice to have an interlaced (15kHz) video option just like in case of the minimig core! It could be activated pressing some magic (i.e. '5' for PAL standard 720x576@50Hz and '6' for NTSC 640x480x60Hz) keys during boot (as I remember, only number keys 1-4 are occupied now). Connecting an old SCART-compatible TV with a minimig VGA2SCART cable would be an authentic and cheap option for us CRT lovers...

  • Trouble with interlace is that the original VIC chip only generates one half picture (the short frame if I remember right), so true interlace will mean running async to the actual VIC picture generation.


    The Minimig will only display interlace when the Amiga is configured to output that mode. This is hardly ever the case on most games, and nobody using a CRT will be happy about the flicker you get on a WB.


    So what I can think of is a mode that bypasses the frame buffer of the Chameleon, and output a 15kHz picture that is V-Synced by nature. This may, however, only be possible in standalone mode, as the synchronisation to the host machine in cartridge mode may break such a sync timing for the monitor. The result would either be "jumpy" pixels or tearing due to use of a frame buffer and increased demands on the monitor's capability to sync to a non-steady VSync signal.


    Further, displaying the debug lines at the top of the screen may also become more difficult, as the number of lines available is rather limited for a 15kHz non-interlace screen. If you enable debug infor for the C64 and both floppy drives, the debug bar may reach down into the text window of the C64.


    So - quite a few "ifs" and drawbacks. To be honest, I find fixing known chip bugs more important.

  • Of course fixing the bugs is the most important, but it would be still a nice feature (not only the minimig, but the Atari 800, the PCE and the MSX cores have the same feature in case of V1 hardware).

  • The Chameleon does have an independent frame buffer, but no independent pixel clock for the output. So while adding the reolutions looks very doable, the resulting H/V frequencies may be so non-standard that only old multisync CRTs may be able to make use of these "new" screenmodes. This may cause a lot of confusion with non-technical users, resulting in lots of support work for us here in the forum...