ColinPitrat
60 hz video output
Hello
I suggest to add a setting in the Video panel to let choose between 50 hz and 60 hz video output. After all, the CPC 6128 was sold in the US with a such a switch on the screen. And there is a jumper in the CPC for that, AFAIK. It may be related to the [Video] Jumpers entry in the config file, isn't it ?
60 hz would allow smoother scrolls on modern screens, as most of them do not support 50 hz (even with custom resolutions). And that would help with video websites at the same time.
I guess some games won't be compatible with 60 hz. That's probably true on real hardware as well anyway.
Interesting. I didn't know the computer was ever sold in the US.
Looking for information about 60Hz CPC I found:
- https://cpcrulez.fr/hardware-6128-cpc_6128-usa-marche_americain.htm
- https://www.cpcwiki.eu/index.php/Screen_refresh_rate
- https://www.cpcwiki.eu/index.php/Amstrad_Whole_Memory_Guide_-_The_machine_pack
And some discussions where the information is less reliable:
- https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/the-schneider-amstrad-cpc-in-the-usa-means-60-hz-and-110-volts/
- https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/60hz-cpc/
It's definitely not a high priority in my eyes, but if someone wants to look into this and provide more info on what this would mean (and bring) to support it in caprice32, I'm interested!
I did some testing.
The code suggests jumpers=0x7f should change the refresh rate.
cap32 -O system.jumpers=0x7f causes Caprice to load with video scrolling, so that suggests a refresh rate issue. The stats suggest that it's at 45 FPS.
Using the 60 hz code from https://www.cpcwiki.eu/index.php/Screen_refresh_rate also causes this same issue
Found https://www.cpcwiki.eu/index.php/LK_Links#LK4_-_Screen_Refresh_Rate which mentions:
The 60Hz setting may cause compatibility problems with various non-BIOS software. And, due to a BIOS glitch, even with BIOS-based software (see SOFT 968 Appendix 13 (XIII) (Hints Tips and Workarounds) for details).