Thread: Ortonview PCB
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Old 7th Jul 2021, 6:08 pm   #30
SiriusHardware
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Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
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Default Re: Ortonview PCB

Just remembered this:

Quote:
The pull up resistors could probably be increased to 100k as they are only used for a static signal level and don’t need to worry about input capacitance
Actually, in typical usage they are not necessarily completely static - for example, one of the four Page Sel inputs is usually connected to TOP PAGE so that the VDU shows the content of two different 256-byte blocks of memory. In addition to this, TOP PAGE can also be connected to the graph / char input, the swap pages input and the inverse video input so that all of those parameters are switched over when the TV scan is half way down the screen.
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