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SiriusHardware · 29th Sep 2020, 9:25 pm

I forgot to mention that for the above to be true, VDU 'Top Page' (b17) will have to be wired to the least significant 'Page select' input (b9), and also 'Reverse Pages' (b15) will have to be connected to GND to make the 'Reverse Pages' feature active.

Taking b15 low alters the behaviour of the TOP PAGE (b17) output so that it is high while the LOWER half of the screen is being rendered. Normally it is high while the UPPER half of the screen is being rendered, hence 'Top Page'.

29th Sep 2020, 9:25 pm	#246
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,570	Re: Mk14 vdu I forgot to mention that for the above to be true, VDU 'Top Page' (b17) will have to be wired to the least significant 'Page select' input (b9), and also 'Reverse Pages' (b15) will have to be connected to GND to make the 'Reverse Pages' feature active. Taking b15 low alters the behaviour of the TOP PAGE (b17) output so that it is high while the LOWER half of the screen is being rendered. Normally it is high while the UPPER half of the screen is being rendered, hence 'Top Page'.