I have some questions about timings in the Oric-1 and Atmos.
Where there NTSC models ever released, or just PAL?
When you set 60Hz mode, i presume thats a 60Hz PAL signal, rather than NTSC?
How many CPU cycles are executed per raster line?
Of the 312 PAL raster lines, on which line does the Oric start/stop drawing video?
Cycle and video timings
Re: Cycle and video timings
No NTSC machines were released.Xeron wrote:I have some questions about timings in the Oric-1 and Atmos.
Where there NTSC models ever released, or just PAL?
When you set 60Hz mode, i presume thats a 60Hz PAL signal, rather than NTSC?
How many CPU cycles are executed per raster line?
Of the 312 PAL raster lines, on which line does the Oric start/stop drawing video?
Re: Cycle and video timings
Yup, PAL 60Xeron wrote:When you set 60Hz mode, i presume thats a 60Hz PAL signal, rather than NTSC?
About 64 cycles at 50hz.Xeron wrote:How many CPU cycles are executed per raster line?
No idea, but this can be figured out by testing the value of the sync line on the socket.Xeron wrote:Of the 312 PAL raster lines, on which line does the Oric start/stop drawing video?
Re: Cycle and video timings
About 64 cycles at 50hz.Xeron wrote:How many CPU cycles are executed per raster line?
Did the display steal that many clock cycles during the display update?
I mean... 1 MHz vs 50 Hz?
Re: Cycle and video timings
well, 1mhz=1000000hzJamesD wrote:About 64 cycles at 50hz.Xeron wrote:How many CPU cycles are executed per raster line?
Did the display steal that many clock cycles during the display update?
I mean... 1 MHz vs 50 Hz?
1000000/50=20000 cycles per VBL
20000/~312=64 cycles
Don't see what is stolen
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Re: Cycle and video timings
Ah, PAL raster lines. That's why it looked off. I was still thinking NTSC.Dbug wrote:well, 1mhz=1000000hzJamesD wrote:About 64 cycles at 50hz.Xeron wrote:How many CPU cycles are executed per raster line?
Did the display steal that many clock cycles during the display update?
I mean... 1 MHz vs 50 Hz?
1000000/50=20000 cycles per VBL
20000/~312=64 cycles
Don't see what is stolen