bitartrate thanks, the chip has a lot of interesting potential, but there's a lot more involved in background... fortunately, for part of I want to do, it looks like i can use SAVE/LOAD PCX, so most of the menu and file handling routines should port over to the Basic Engine fairly easily. I'd really like to port over as Sprite editor I've been working on but I've got to get a better handle on how Sprites are handled, and understand the PCX file format, so for now, it's a basic translation program and some utility programs, like a file browser, that I typically like do to learn the machine and build up a function library.
it was the VREG($01), which should be the read version of VREG... On GIT, I'm being told $01 is the "write status register", where $05 is the read, so I'm assuming they mean the VREG read is using wrong opcode.