Here, I finally have multiple lines of star bursts displayed.

Multiple Lines with SCELBI Oscope Output

My problem was that I had the input port data bus hooked up wrong. When I connected it, I assumed that the edge connector would be wired from data bit 0 to data bit 7 in order, but that wasn’t the case. I also had to turn off the invert switch on the scope. The problem with inverted characters will have to be investigated further.

I also have a good understanding of adjustments for Horizontal Width (R10), Horizontal Speed Balance (R6), Vertical Speed Balance (r17) and Tilt (R20). The speed balance adjustments are necessary to make sure that movements left and right are at the same speed and movements up and down are at the same speed.

I still need to figure out what’s happening at the beginning of each line and at the beginning of the page.

The driver implementation is being investigated. It promises to be a serious challenge to fit it in 256 bytes, as half of it will be taken up by an ASCII to 2 byte output table.