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JDW

SE/30 CMD-CTRL-POWER Reset

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A good number of Macs can use the Command-Control-Power keyboard combination to reset, but as I recall the SE/30 cannot.  Indeed, the power key (has an arrow pointed left) itself cannot be used to power on the machine which is why I purchased a Sophisticated Circuits PowerKey Classic about 10 years ago to enable that feature.  But do any of you remember the technical reason why Command-Control-Power doesn't work on the SE/30?

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Wouldn’t it be technically related to “softpower” capability, which requires both ps and logic board support, and in some systems, it seems, System software (the Autopower On Control Panel, or whatever)? Some of the later Mac functionalities required a clock, I seem to recall.

 

Obviously, on an SE/30, there’s a switch round the back. Once running, though, you’ve got something akin to what you want in the programmer’s/ reset and interrupt button around the side;  it is possible to do some mildly interesting things via the programmer’s button, including a soft reboot. Maybe that was the engineers’ expectation. It’d be interesting to know whether or not the “three fingered salute” simply duplicated what you can do via the programmer’s switch and the command line that comes up there.... Anyone know?

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The SE and SE/30, like all compacts, come with programmers switches. That is what was used before the keyboard commands were made.

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5 hours ago, LaPorta said:

The SE and SE/30, like all compacts, come with programmers switches. That is what was used before the keyboard commands were made.

My understanding was that control-command-power was an Apple II keyboard combination originally, and as we know the Apple II predates the Macintosh. 

 

Consider also photos of the MacIntosh SE/30 and it’s stock condition which shows a power key on the keyboard:

 

https://apple-history.com/se30

 

 Why put the power key on the keyboard if it’s not going to be used in some way on the particular Macintosh with which the keyboard shipped ? 

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26 minutes ago, JDW said:

My understanding was that control-command-power was an Apple II keyboard combination originally, and as we know the Apple II predates the Macintosh. 

Your understanding is somewhat correct. The key sequence "Command-Control-Power" originated with the Apple Desktop Bus keyboard and microcontroller. The first Apple computer to feature ADB was the Apple IIgs, introduced in September 1986. The first Macintosh computers with ADB were the Macintosh SE and Macintosh II of March 1987. Both models had physical reset and interrupt switches, but the Macintosh II had soft-power-on from the keyboard Power key.

 

 

Quote

Consider also photos of the MacIntosh SE/30 and it’s stock condition which shows a power key on the keyboard:

 

 Why put the power key on the keyboard if it’s not going to be used in some way on the particular Macintosh with which the keyboard shipped ? 

As ADB was intended to be a standard among both the Apple IIgs and Macintosh line, it was deemed prudent to have standardized keyboards that featured a Power Key.

 

Why make different models of keyboard for each model of Macintosh?

Edited by Dog Cow

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8 hours ago, beachycove said:

Wouldn’t it be technically related to “softpower” capability, which requires both ps and logic board support, and in some systems, it seems, System software (the Autopower On Control Panel, or whatever)? [...]

 

Obviously, on an SE/30, there’s a switch round the back.

And on a Mac LC, there is also a hard switch round the back, yet the LC responds to the keyboard Reset and Interrupt commands. 

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7 minutes ago, Dog Cow said:

As ADB was intended to be a standard among both the Apple IIgs and Macintosh line, it was deemed prudent to have standardized keyboards that featured a Power Key.

 

Why make different models of keyboard for each model of Macintosh?

 Right. And since ADB is a standard feature of the SE/30, why then doesn’t it take full advantage of that in terms of the power key on the keyboard and the reset keystroke we’re talking about?

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1 minute ago, JDW said:

 Right. And since ADB is a standard feature of the SE/30, why then doesn’t it take full advantage of that in terms of the power key on the keyboard and the reset keystroke we’re talking about?

Maybe Apple's engineers didn't want to redesign the analog board and power supply to support soft power? The Macintosh II was a brand-new architecture. Maybe they just wanted to keep things incremental in the compact Mac line.

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6 hours ago, LaPorta said:

The SE and SE/30, like all compacts, come with programmers switches. That is what was used before the keyboard commands were made.

The Macintosh IIsi and the Macintosh LC, part of Apple's trio of low-cost computers of the early 90s, were the first models which did not have physical reset and interrupt switches, and which used the keyboard commands instead.

 

My guess is that Apple's engineers didn't want to redesign the compact Mac analog board and power supply to support soft power, which is why the Mac Classic and Classic II retained the physical switches on the left side.

Edited by Dog Cow

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1 hour ago, JDW said:

My understanding was that control-command-power was an Apple II keyboard combination originally, and as we know the Apple II predates the Macintosh. 

 

Consider also photos of the MacIntosh SE/30 and it’s stock condition which shows a power key on the keyboard:

 

https://apple-history.com/se30

 

 Why put the power key on the keyboard if it’s not going to be used in some way on the particular Macintosh with which the keyboard shipped ? 

There are tons of later machines, Quadra 660AV/PM6100 for example, where the "power" key did nothing to start it, but worked to utilize the restart and shut down shortcuts.

 

Part of the reason is that each and every ADB keyboard was made to a standard where all would be interchangeable. That's why you can even use a IIgs keyboard with a Mac, and Mac keyboards with a IIgs. So, even if a certain key did not provide functionality on a particular Mac, they all had the same types of keys to be consistent, and have backwards compatibility.

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The electrical reason for all of this, the power key on the keyboard is wired to its own pin the ADB connector. 

 

Guess what? its not wired up to anything on the SE/30 board. Thats why it doesnt, and would never work. But, what I Dont know is if the pin on the ADB connector is actually physically connected to the switch, or if its part of the matrix and that is simply an output from the keyboard's microcontroller. 

 

However if this was the case, it would need standby voltage to the keyboard at all times which I dont think it has outside of the power key wire. 

Edited by techknight

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1 hour ago, techknight said:

The electrical reason for all of this, the power key on the keyboard is wired to its own pin the ADB connector. 

 

Guess what? its not wired up to anything on the SE/30 board. Thats why it doesnt, and would never work. But, what I Dont know is if the pin on the ADB connector is actually physically connected to the switch, or if its part of the matrix and that is simply an output from the keyboard's microcontroller. 

 

However if this was the case, it would need standby voltage to the keyboard at all times which I dont think it has outside of the power key wire. 

I'm game for an SE/30 motherboard hack to make it work!  :-) We hack/upgrade pretty much everything else on the SE/30, so why not, right?

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2 hours ago, beachycove said:

The Pkey INIT referenced three posts back in the link from DogCow would be interesting to try on the SE/30.

It's an INIT that triggers an interrupt to access MacsBug when you press the Power key. Programmer's Key, distributed with MacsBug 6.2.2, does the same thing.

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The Programmers’ Key INIT does indeed work with an SE/30, and it can be configured to either interrupt (trigger Macsbug) or soft restart when the power key is pressed with various modifier keys. The SE/30 is indeed physically capable of recognizing when the power key is pressed — it just doesn’t do anything by default. You can even check for it yourself if you can do a little Toolbox programming ... just call GetKeys() and check for virtual key code 0x7F (127).  (It’s listed as “7F7F” in Inside Macintosh, but that’s a typo ... virtual key codes are just one byte long.).  

 

    KeyMap km;

    GetKeys(&km);

    if (km[0x7F])

    {

        /* power key is pressed! */

    }

 

See Inside Macintosh: Macintosh Toolbox Essentials on p. 2-42, e.g. at https://developer.apple.com/library/archive/documentation/mac/pdf/MacintoshToolboxEssentials.pdf .

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Interesting thread. I have the SeaSonic PS in one of my SE/30s and a SeaSonic in my IIci. To get the softpower to work, I had to follow the lead of @superjer2000 in a post in this forum that I can't find. It is a small board that got the softpower working fine in the IIci with the SeaSonic PS.  If one was to out that same board in a SE/30 with the SeaSonic PS, would it have softpower?

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8 hours ago, Von said:

Interesting thread. I have the SeaSonic PS in one of my SE/30s and a SeaSonic in my IIci. To get the softpower to work, I had to follow the lead of @superjer2000 in a post in this forum that I can't find. It is a small board that got the softpower working fine in the IIci with the SeaSonic PS.  If one was to out that same board in a SE/30 with the SeaSonic PS, would it have softpower?

 

Well, because as techknight said the ADB pin carrying the power key signal isn’t wired to anything on the SE/30 motherboard (just to be clear, my observation above was the SE/30 can recognize the power key in software just like any other key, so an INIT like Programmers Key can work ... but I have no doubt TK is correct that the motherboard doesn’t get a dedicated signal from it), one would have to wire up the SeaSonic PSU to the ADB plug directly somehow, I’m not sure if there’s an elegant way to do that.  Then probably add an inverter or whatever else is necessary for it to play nicely with SeaSonic soft power, which as I recall expects PS/ON shorted to GND (this is what @superjer2000 described in the IIci soft power thread I think?).  Personally I also use a Sophisticated Circuits PowerKey so I haven’t looked into this.  But if we tried it, I think it would work?

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However you would need some way to keep PS/ON shorted to ground once you release the button again so you want to latch and invert it at least.

Also you would have to think about how to make it shut down again.

There is a reason for the power circuit made from 74 logic in the other II machines is kind of complex.

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Oh right ... yes, I guess it’s slightly easier if we only ever care about being able to turn it on. :)  The shutdown problem is way harder, no idea how to extract the right signal out of software on an SE/30.

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You could see what happens with the /PFW line if you select "shutdown" from the menu. If it is pulled low by VIA2 then you can tap in there and have the power supply turn off.

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Here is the link to the board that needed to be added to the SeaSonic PS to get softpower: 

 

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@Von In other words, you are using an NPN transistor (and resistors) to make a simple investor, such that when the transistor is OFF the output is HI (i.e., Seasonic PSU disabled), and when the transistor is switched ON the output is GND (i.e., Seasonic PSU enabled).

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I'm curious if that Power button key thing can be used to perform reset and interrupt functions in substitution of the hardware reset and interrupt buttons? Those plastic hardware reset switch thingys are not that common, but also delicate.

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1 hour ago, Mk.558 said:

I'm curious if that Power button key thing can be used to perform reset and interrupt functions in substitution of the hardware reset and interrupt buttons?

Sure. If the Power key can be detected by software, you can have a little routine call the _Debugger trap. The Motorola 680x0 has a RESET instruction which could be executed for Reset. It wouldn't be exactly the same as the physical switches though, because it's dependent on your little routine being able to run.

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