Re: A86: Dead list?
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Re: A86: Dead list?
David Phillips wrote:
>
> You're close, it's port 0. Port 2 is contrast.
>
> Mode 0 sucks? I don't know why you say that, but it isn't used on the
> calculator. In mode 0, instructions place an instruction on the data bus to
> be executed. If you set mode 0, random instructions would be executed, no
> doubt causing the calc to crash.
Interestingly it doesn't, the instruction executed is always rst 38h.
There was a thread about this a couple months back I think...
> Mode 2 is the fastest, but requires at least 300-400 bytes. If you
> absolutely need the fastest interrupts, go with mode 2. But for other
> situations, mode 1 works the best.
It is possible to do mode 2 using only 260 "extra" bytes by putting a jp
in the proper location. Either way it's going to take up space within
your program, which is (usually) the only thing that matters... IM 2
has the benefit of not screwing with the user's TSRs though.
> Despite what the 86 Central grayscale
> tutorial says, interrupt speed has _nothing_ to do with grayscale quality.
> That's all in the mixing ratio. 1:2 will achieve flicker free grayscale
> (flourescent lighting seems to make flicker noticable), no matter how slow
> the interrupts (unless you start missing them...).
Sunlight also does it :(
References: