[Coco] Instruction cycles per 60Hz frame.

[Ed Snider]

Sure, you could do that, it's about 15 cycles more per vsync (.89MHz) and 30 @ double speed. 

- Ed


> On Nov 17, 2019, at 3:52 PM, Alex Evans <varmfskii at gmail.com> wrote:
> 
> Is it worth taking into consideration that the 60Hz should actually be
> 59.94Hz assuming NTSC (30/1.001 full frames or 60/1.001 half frames).
> 
> On Sun, Nov 17, 2019 at 2:39 PM Ed Snider <zippster278 at gmail.com> wrote:
>> 
>> Correct.  Round down to the nearest whole cycle of course.
>> 
>> 894886 cycles per second at single speed.
>> 1789772 cycles per second at double speed.
>> 
>> - Ed
>> 
>> 
>>> On Nov 17, 2019, at 12:41 PM, James Ross <jrosslist at outlook.com> wrote:
>>> 
>>> continued:  actually the math can simplified to ...
>>> 
>>> cycles_per_60hz_frame = (1d / 60d) * 1000000 * coco_clk;  // 0.8948... MHz
>>> double_cycles_per_60hz_frame = (1d / 60d) * 1000000 * double_speed; // 1.789... MHz
>>> 
>>> which gives the same results:
>>> standard 60hz (vsync) frame = 14914.7727272727 cycles per frame
>>> double speed 60hz (vsync) frame = 29829.5454545455 cycles per frame
>>> 
>>> so, unless I am really confused (which is quite possible!), then the #'s above have to be correct ... ok moving on then :) :)
>>> 
>>> james
>>> 
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>> 
>> 
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