Supercon 2023: James Lewis Builds His Own Portable Apple IIe

[@higaski]

What a journey, great talk

[@bald_engineer]

Thanks!

[@SojournerDidimus]

26:20 I remember one of the Apple II machines had this "clever" trick with a Green/Magenta screen, where is could either drive both the green and the magenta subpixels, *or* the green from one and the magenta from the adjacent pixel! They used this to double the solubility (not the resolution) of the screen. Like a predecessor to modern anti-aliasing. Might it be that the Mega II has a similar trick, where it "knows" the arrangement of the subpixels and shifts them over per subpixel instead of per pixel to add to the apparent resolution? You could try outputting to a genuine IIe display to see if it "works".

[@bald_engineer]

The IIGS's composite circuit, which I used for the early stages of the project, doesn't output the same composite signal as the IIe. Mega's 4-bit RGB signals and SERVID (the luma/chroma data for each line) output the same data. The 4-bit RGB signals are a de-muxed copy of SERVID. Unfortuantely, SERVID does not behave exactly like the SERVID on the II+/IIe.