In T200, the video subsystem was really reworked to take advantage of hardware scrolling. >From a quick scan, it seems like the basic operation is the same for M100 and T200 (upper and lower portions of the LCD), so the same "organization" should be applicable to the M100.
Could T200 video subsystem be back ported to M100? Perhaps a much deeper dive into the code could make the M100 truly work as well as the T200 from this perspective, but I would worry that the end result would be so substantially different that software compatibility may become an issue. I guess they got away with software scroll on M100, but T200 would have been completely unacceptable with such a slow scroll across 16 lines rather than 8. Anyhow, I have streamlined the patch now to only 95 bytes, leaving 55 bytes for more stuff. I may try to augment what is there with coverage for some of the additional scroll corner cases. Steve On Wed, Feb 23, 2022 at 10:48 AM Joshua O'Keefe <maj...@nachomountain.com> wrote: > > On Feb 23, 2022, at 7:17 AM, Stephen Adolph <twospru...@gmail.com> > wrote: > > I did a write up on the two patches that are needed. > > Steve, I remember seeing you mention this a while back and I'm glad you > were able to get back to it. Your write-up was clear, informative and > interesting. Thanks for sharing it. > > I wonder why this controller feature was never exploited. Was there > perhaps a similar, earlier part lacking the feature that was swapped out > late in the design cycle? Simple time constraints like every engineer in > history has faced? I can imagine all kinds of scenarios and it's a shame > we'll never know the real story of why the ROM is the way it is.
