Custom refresh rate like in BMC64?
Posted: Mon May 20, 2019 8:45 pm
Hi there, Jon!
I dont know if you recall this, but I have reported several times that using the custom video mode for the PiTop will cause games with smooth scroll to show hiccups once in a while.
I also have an HDMI screen with the same native resolution as the PiTop screen, 1360x768. The results when using that mode are the same, with the occasional hiccups in framerate.
I reported it to rrossi, the BCM64 creator (BMC64 is THE baremetal C64 emulator for the Pi, no OS involved), because I had the same problem with BMC64, and he fixed it!!!, look: https://github.com/randyrossi/bmc64/blo ... .md#timing
So now, I have this on config.txt:
And this on cmdline.txt (this is specific for BCM64, because it derivates the emulated cycles from real exact vsync rate):
...And the native 1360x768 50Hz mode works great with BMC64, on the PiTop too! No more hiccups!
This is because 1360x768 50Hz is NOT exactly 50Hz, but 49.89Hz, and BMC64 takes this into account, while ADFFS does not.
So, could you please implement a solution for custom "floating point" framerates when a custom mode is used? That would bring perfect refresh rate to ADFFS, like in BMC64.
I dont know if you recall this, but I have reported several times that using the custom video mode for the PiTop will cause games with smooth scroll to show hiccups once in a while.
I also have an HDMI screen with the same native resolution as the PiTop screen, 1360x768. The results when using that mode are the same, with the occasional hiccups in framerate.
I reported it to rrossi, the BCM64 creator (BMC64 is THE baremetal C64 emulator for the Pi, no OS involved), because I had the same problem with BMC64, and he fixed it!!!, look: https://github.com/randyrossi/bmc64/blo ... .md#timing
So now, I have this on config.txt:
Code: Select all
# Custom 1360x768 50Hz
hdmi_cvt=1360 768 50 3 0 0 0
hdmi_group=2
hdmi_mode=87
Code: Select all
machine_timing=pal-custom cycles_per_refresh=980670
This is because 1360x768 50Hz is NOT exactly 50Hz, but 49.89Hz, and BMC64 takes this into account, while ADFFS does not.
So, could you please implement a solution for custom "floating point" framerates when a custom mode is used? That would bring perfect refresh rate to ADFFS, like in BMC64.