Hi.
I have an idea.
And since I am a n00b, and this is the "N00b Questions" section ... well, here goes.
I very soon will receive the LaST 4MB upgrade for my ST, and there is a bridge (which can be pared with a switch) to switch on or off the 4MB expansion (yes, technically, we only disable the addressline, but the effect is the same).
I saw a vid from Adrian Digital Basement where a memory expansion could be disabled by holding the mousebutton during poweron of a Classic Macintosh.
So I got to thinking; that should not be hard at all.
So, here is the idea;
From the mouse button (that's a dedicated pin, pin 6) to the Data port of a D-Type Latch (74LS75, iirc), and from the reset line to the Control port of that latch, that should give a High output on the output if the mouse button was held down during reset, and the inverted output would then be low.
From the inverted output to the base of an NPN transistor, the collector to the address line, and the emitter to the "other side" of the jumper/switch/bridge on the expansion module ...
Would/should this work??? (Maybe it could even be an improvement on the module itself, but let's not get carried away here...)
Now, what I am totally not sure about is what type of transistor or if I have it the correct way round (as in; should I swap C and E), but the idea itself; it's feasable, right? anyone here with logic/electronics/TTL knowledge here to mature this idea?
(If it's stupid, just tell me, I can take it ... )
The alternatives are
- creating or finding a hole in the case for a toggle switch
- opening the case everytime the 3 extra megabytes need to be disabled.
Yes, I know, this should not happen very often, or even at all, but 1. it's a challenge and 2. it's neat to have the option to revert to 1 MB temporarily without damaging/opening the case.
R.
"Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
"Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
--
Just a 50-ish-YO that cannot decide to be a grown-up.
Highlights of my collections;
- Commodore C64c, A+ grade
- C64c homebrew (SX64 colors)
- C64 Breadbin "Aldi"
- 1581 in perfect condition
- Amiga 500 (needs work)
- Amiga 1200, A+
- 1084S-P1 in great shape
- Atari 1040STFM, in great shape, with SM124 (Retr0Brite needed)
Most appreciated purchase of 2024;
- ZD-915 desoldering cow.
You can find me on;
- GitHUB
- Thingiverse
- Printables
My passion;
- Retro Repair and Collecting
Just a 50-ish-YO that cannot decide to be a grown-up.
Highlights of my collections;
- Commodore C64c, A+ grade
- C64c homebrew (SX64 colors)
- C64 Breadbin "Aldi"
- 1581 in perfect condition
- Amiga 500 (needs work)
- Amiga 1200, A+
- 1084S-P1 in great shape
- Atari 1040STFM, in great shape, with SM124 (Retr0Brite needed)
Most appreciated purchase of 2024;
- ZD-915 desoldering cow.
You can find me on;
- GitHUB
- Thingiverse
- Printables
My passion;
- Retro Repair and Collecting
Re: "Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
The mouse is connected to the keyboard's microcontrôleur, that send messages to the main board through a serial link to a serial adapter that IS then managed by the TOS to handle HID évents.
So what you see is not doable. What IS doable through, that I saw done for switching between ROMs images (smartboard by black cat, switchless TOS selector by retroluna) is to snoop over that serial line. You need a microcontroller to drive.a transistor that will activer as a action able switch on that target address line.
Have fun with that project.
So what you see is not doable. What IS doable through, that I saw done for switching between ROMs images (smartboard by black cat, switchless TOS selector by retroluna) is to snoop over that serial line. You need a microcontroller to drive.a transistor that will activer as a action able switch on that target address line.
Have fun with that project.
- chronicthehedgehog
- Site sponsor
- Posts: 309
- Joined: Sun May 08, 2022 6:11 pm
- Location: The Midlands
- Contact:
Re: "Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
Apologies, slightly off topic but related:
I've been hacking a few joy pads to work with the ST recently and I've been puzzled why the STs designers would connect the mouse buttons to the enable pins on the joystick port MUX and carry the button signals (with joy 1 pin 5) over to the mode selection pins on the 6301. This is a contributing reason why this wouldn't work sadly. Although a fine idea.
It would suggest that they envisioned changing the keyboard processor's mode with the mouse buttons. Do any controllers/peripherals exist that use this feature?
I've been hacking a few joy pads to work with the ST recently and I've been puzzled why the STs designers would connect the mouse buttons to the enable pins on the joystick port MUX and carry the button signals (with joy 1 pin 5) over to the mode selection pins on the 6301. This is a contributing reason why this wouldn't work sadly. Although a fine idea.
It would suggest that they envisioned changing the keyboard processor's mode with the mouse buttons. Do any controllers/peripherals exist that use this feature?
Re: "Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
Hmmmmm, I see...
Weird design choice
Guess I'll have to go with a switch then ... Maybe I can tuck one in the cartridge port (off to one side where it would not interfere with a cartridge, but also completely hidden from view... Yes, I am THAT anal about drilling holes into vintage computers
Thank you both for your input. Back to the drawingboard
Weird design choice
Guess I'll have to go with a switch then ... Maybe I can tuck one in the cartridge port (off to one side where it would not interfere with a cartridge, but also completely hidden from view... Yes, I am THAT anal about drilling holes into vintage computers
Thank you both for your input. Back to the drawingboard
--
Just a 50-ish-YO that cannot decide to be a grown-up.
Highlights of my collections;
- Commodore C64c, A+ grade
- C64c homebrew (SX64 colors)
- C64 Breadbin "Aldi"
- 1581 in perfect condition
- Amiga 500 (needs work)
- Amiga 1200, A+
- 1084S-P1 in great shape
- Atari 1040STFM, in great shape, with SM124 (Retr0Brite needed)
Most appreciated purchase of 2024;
- ZD-915 desoldering cow.
You can find me on;
- GitHUB
- Thingiverse
- Printables
My passion;
- Retro Repair and Collecting
Just a 50-ish-YO that cannot decide to be a grown-up.
Highlights of my collections;
- Commodore C64c, A+ grade
- C64c homebrew (SX64 colors)
- C64 Breadbin "Aldi"
- 1581 in perfect condition
- Amiga 500 (needs work)
- Amiga 1200, A+
- 1084S-P1 in great shape
- Atari 1040STFM, in great shape, with SM124 (Retr0Brite needed)
Most appreciated purchase of 2024;
- ZD-915 desoldering cow.
You can find me on;
- GitHUB
- Thingiverse
- Printables
My passion;
- Retro Repair and Collecting
- russellnash
- Site sponsor
- Posts: 142
- Joined: Fri Mar 26, 2021 2:46 pm
Re: "Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
I put a jumper under the cartridge port.
Re: "Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
Only original disk based games suffer from too much RAM and the majority of those that did have been patched to work with 4MB when being converted to work from HDD.
If you can find something that doesn't work with 4MB and doesn't have a patch you could ask Dbug or Pera Putnik and I'm sure they would look at it.
If you can find something that doesn't work with 4MB and doesn't have a patch you could ask Dbug or Pera Putnik and I'm sure they would look at it.
Principal ASIC Engineer - SystemVerilog, VHDL
Thalion Webshrine - http://thalion.atari.org
STf,STfm,STe,MegaST,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
Thalion Webshrine - http://thalion.atari.org
STf,STfm,STe,MegaST,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
Re: "Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
I've seen addons that perform switching based on a long reset. That may be simpler than a mouse button?
Some kind of RC network that toggles the switch if reset is held more than 5 seconds or similar?
BW
Some kind of RC network that toggles the switch if reset is held more than 5 seconds or similar?
BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
Re: "Switchless" 1MB/4MB on LaST Upgrade - an idea, perhaps good, possibly bad
Sounds complicated
Based on other messages, I think I'll keep it in 4MB mode, if I ever get it working, as that upgrade failed and in the process, my system got damaged, see hardware forum, cannot link yet as the post awaits moderation.
Based on other messages, I think I'll keep it in 4MB mode, if I ever get it working, as that upgrade failed and in the process, my system got damaged, see hardware forum, cannot link yet as the post awaits moderation.
--
Just a 50-ish-YO that cannot decide to be a grown-up.
Highlights of my collections;
- Commodore C64c, A+ grade
- C64c homebrew (SX64 colors)
- C64 Breadbin "Aldi"
- 1581 in perfect condition
- Amiga 500 (needs work)
- Amiga 1200, A+
- 1084S-P1 in great shape
- Atari 1040STFM, in great shape, with SM124 (Retr0Brite needed)
Most appreciated purchase of 2024;
- ZD-915 desoldering cow.
You can find me on;
- GitHUB
- Thingiverse
- Printables
My passion;
- Retro Repair and Collecting
Just a 50-ish-YO that cannot decide to be a grown-up.
Highlights of my collections;
- Commodore C64c, A+ grade
- C64c homebrew (SX64 colors)
- C64 Breadbin "Aldi"
- 1581 in perfect condition
- Amiga 500 (needs work)
- Amiga 1200, A+
- 1084S-P1 in great shape
- Atari 1040STFM, in great shape, with SM124 (Retr0Brite needed)
Most appreciated purchase of 2024;
- ZD-915 desoldering cow.
You can find me on;
- GitHUB
- Thingiverse
- Printables
My passion;
- Retro Repair and Collecting