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Re: Apple //e's inverted screen?
- Subject: Re: Apple //e's inverted screen?
- From: "David Wilson" <mcs6502@gmail.com>
- Date: 1 Oct 2006 18:05:25 -0700
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Bryan Parkoff wrote:
> Okay, lets say if ALTVID' has low signal. Will the screen be inverted
> including inverted 16 colors?
No. As I said - if ALTVID' is low, the video will be high (white if
ALTVID' is low for at least 2/7 of a microsecond).
> Will it show white border in the top, bottom,
> left, and right margin?
The margins are normally black due to the signal WINDW' (aux-7) from
the IOU chip driving OE' on the chargen. As ALTVID' is connected after
the LS166 parallel->serial chip this means that ALTVID' can even
override the black margins. So yes, you can use ALTVID' to make the
margin white.
> Is it possible to wire ALTVID's pin to AN2. I would leave ENVID signal alone.
Yes but as the fastest you can turn it on or off would be every 4
machine cycles the shortest line you could make would be 28 hires
pixels (4 characters) wide.