Re: [M100] M100 LCD repair video and alternative use for unused screen RAM
On Wed, Jun 15, 2022, 6:34 PM Daryl Tester < dt-m...@handcraftedcomputers.com.au> wrote: > > ALTLCD comes to (ageing and decrepit) mind? > ALTLCD is in RAM, it has character data. I think Jeff was talking about unused portions of the display components themselves. There are 10 display drivers and parts are unused at the edge of the screen. It isn't like peeking and poking ram, it's accessed via I/O instructions. You can put data there but it requires special logic. You can't use it for code, at least not code you want to run directly. And I don't recall whether it survives power on/off. Aside from Jeff, I think Ken Pettit has experimented with it. And maybe Ron Weisen once upon a time? Vague recollection his special file management tools made some use of it. Could be wrong. -- John.
Re: [M100] M100 LCD repair video and alternative use for unused screen RAM
I've thought a few times about using that area. I never have because to access the data requires more work and code that the system ram. So far I've decided not to spend the code. For Rex, that space isn't available on T200 so I've not used it on that project. I guess it's not a lot of code though. I could probably use it as lcd state storage on the m100 on the hardware scroll implementation rather than the Hayash directory entry. But it would use precious patch space in the rom. I enjoyed that video! LCD is tricky to work on. On Wednesday, June 15, 2022, Daryl Tester < dt-m...@handcraftedcomputers.com.au> wrote: > On 16/6/22 03:58, bir...@soigeneris.com wrote: > > When learning how the screen RAM load save worked it occurred to me that >> the RAM >> for the unused segment drivers is also unused. It got me wondering if >> anyone >> had ever used these bytes as a hidey hole for data, etc. It would be a >> pretty >> sneaky place to hide something. >> > > I thought Steve and John (and others) have spoken about this at length on > this list - > ALTLCD comes to (ageing and decrepit) mind? > > Cheers, > --dt >
Re: [M100] M100 LCD repair video and alternative use for unused screen RAM
On 16/6/22 03:58, bir...@soigeneris.com wrote: When learning how the screen RAM load save worked it occurred to me that the RAM for the unused segment drivers is also unused. It got me wondering if anyone had ever used these bytes as a hidey hole for data, etc. It would be a pretty sneaky place to hide something. I thought Steve and John (and others) have spoken about this at length on this list - ALTLCD comes to (ageing and decrepit) mind? Cheers, --dt
[M100] M100 LCD repair video and alternative use for unused screen RAM
Hi guys, I did a video on M100 LCD repair a few weeks ago but for got to post about it here. Link below. As part of the diagnostic process, I took a program I found in the M100 archives and added a basic GUI so you can fill the screen black, clear the screen and load/save the screen. I used the alternating clear/black fill to test the segment drivers and the ability to save the screen RAM to test the RAM in the LCD drivers. When learning how the screen RAM load save worked it occurred to me that the RAM for the unused segment drivers is also unused. It got me wondering if anyone had ever used these bytes as a hidey hole for data, etc. It would be a pretty sneaky place to hide something. https://youtu.be/gtSlnKx51SQ Jeff Birt (Hey Birt!)
Re: [M100] Bump
Happy summer (almost). It's wet and rainy in (normally) sunny Alberta. We're in the midst of moving to a smaller city, so all my m100 stuff is packed. Haven't touched it in a month or so other than to carefully package it up for transport. I did manage to get a new (old) toy though -- a great looking SHARP EL-5804 calculator that I used to own back in the late '70s https://imgur.com/uZqtAmf Though I'm looking forward to unpacking and getting back to a few 8201a that need work. --Brad On Wed, Jun 15, 2022 at 8:04 AM Bruce H McIntosh wrote: > > Hope everyone is enjoying their summer :-) > > > > -- John > > > > This week ‘summer’ has officially begun here, temps near 100F and very > humid.> > Jeff Birt > > So the adjective for which we're searching is more "enduring" than > "enjoying"? :D > > This is the kind of weather that taught me the hard way not to store old > laptops in the garage. > > -- > > Bruce H. McIntosh bhmcint...@gmail.com www.afn.org/~scotsman WA4UF > > Network geek with a strong affinity for Telecasters > > -- -- Brad Grier
Re: [M100] Bump
Hope everyone is enjoying their summer :-) -- John This week ‘summer’ has officially begun here, temps near 100F and very humid.> > Jeff Birt So the adjective for which we're searching is more "enduring" than "enjoying"? :D This is the kind of weather that taught me the hard way not to store old laptops in the garage. -- Bruce H. McIntosh bhmcint...@gmail.com www.afn.org/~scotsman WA4UF Network geek with a strong affinity for Telecasters
