Soft ps mod for hard ps macs & apple II's

[barana]

This is a split topic taken from viewtopic.php?f=29&t=17789

I wonder If there is a way that a soft start (power/reset key from keyboard) power supply can be used on an earlier hard ps based mac/A2

What wiring/chip mods would be required?

and as an encore, can it be controlled by the system for shutdown without touching the power/reset key ie full software shutdown
- another addition - an init or something be written for Mac sys 6.x GSOS 6.0.1 so that it sends the appropriate signal to shutdown power.

cmon add your 2c...

[techknight]

I dont have a macintosh classic or classic II system. But with the SE and SE/30 its REEEEEEEEEEEL Simple actually. With the SE/30 someone else discovered the PwrOff connection on the secondary VIA is present so soft-shutdown is easy.

I cannot speak for the classic and classic II. But say if it was not present, then shutting down the system automatically powering it off as well would be much more trivial. Not impossible, as adding your own VIA to the expansion connector, or even patch it into the address/data GLU chip is easy enough to add automatic power-off shutdown capability (using bbrauns shutdown INIT tailored to the proper hardware mechanism of course).

If this isnt a concern, another way to go about it is once your at the safe to turn off screen, you could program a PIC or AVR if you press/hold the power button, itll power-down. As well as power up when you press the button.

Its all real easy. If i knew a little bit more about which exact systems your using and if you desire automatic power-off during shutdown will help me derive a schematic. Maybe next weekend ill make my Mac soft-power capable and explain it.

[barana]

Its all real easy. If i knew a little bit more about which exact systems your using and if you desire automatic power-off during shutdown will help me derive a schematic. Maybe next weekend ill make my Mac soft-power capable and explain it

YES YES YES! please!

Well a compact mac ultimately a mac plus would rock! but i think the whole thing may require an adb mac so a classic/se30
(I do wonder how i will get a soft startup ps to fit into a compactmac -would a colour classic ps do?

and an apple IIGS would be the second one I would like to mod - It came with adb and im thinking a compact/si ps maybe (is the IIis ps even softpower enabled)

I do like the pic/avr idea for 8 bit apple iis/other pc's done in straight hardware no os necessary
this is quite exciting!

[techknight]

I am going to modify my power supply to run soft/start instead of shoehorning in an ATX. ATX is the easiest for normal modders, but modifying the original supply to work soft-start is cleaner/easier for me. But thats just me.

I thought I had a sony and an Aztec supply, but both my supplies are Aztec. would like to get my hands on a sony as well. The sony will be an easy one to mod to be soft-start.

The aztec isnt as easy, because not only does it have a PWM circuit that runs it, it also has a "tickler" circuit that sends pulses in the MOSFET to build a small voltage on the secondary windings. This in turn power and kick-starts the PWM circuit which eventually takes over. So in the Aztec, i would have to stop the PWM controller, AND tickler to put it in stand-by.

Problem: the tickler and PWM are on 2 different reference planes. weeeeeeeeee... fun.

[barana]

these sony and aztec ps' out of what macs are they from? and will they fit in an se/30?

oh i see, i reread, ur going to mod ur current ps to do the job!

I'm salivating here! hehe

[techknight]

Yes. I had thought about just using a simple relay and cutting the mains connection to the Aztec. But I still need a constant 5V for standby current. So, That is why I just rather purposely shut down the power supply into standby, and just draw current from the tickler circuit.

The sony power supplies, they have a whole separate voltage reg for the PWM chip, So i can draw it from there

[Trash80toHP_Mini]

ATX PSU replacements are for hackers who need MORE POWER!!!!!!!!
ATX is also for the unfortunate ones who have a dead Mac PSU on their hands . . .
. . . currently, I fit both categories.

[techknight]

Or you can fix the original PSU. But Its not hard to do both cases. ATX and NON-ATX. no problem. Need one of those slimline/HP style ATX supplies to fit inside the SE and SE/30.

But then theres the mac 128/512/plus which has an embedded power supply to the analog board. But then again, theres no power button on the keyboard either

[barana]

@trash80tohpmini

yeah i would like to use also the atx/itx idea for my ppc amiga so it can have soft powerup/down with a usb kb..looking forward to this!

[Dennis Nedry]

One could utilize the logic of a flip-flop and the power of a relay to soften a power supply. Trickle power could be a simple as cracking open a cell phone charger and shoving that into the mix, or do as the Mac II/x/fx and add an extra PRAM battery or two.

[techknight]

Yea, theres 10000 different ways to do it. Ill do it my way, if someone wants to do it their way, by all means. and please share

[Dennis Nedry]

This is sort of what I was talking about in a general sense. The flip flop can be constructed out of a single quad 2-input NOR gate chip. I'm not sure if this is considered a "flip-flop", per se, it's more of a latch I guess. I agree that there are probably 10,000 ways to do this, but for each person there should be one single method that is the best balance of cheap, easy, and reliable. I am definitely interested to see other methods - it makes us all better at this stuff to see different approaches.

This approach also uses some assumptions: It assumes that the ADB keyboard pulls the power pin low and that the soft power pin goes high to turn off the Mac. (The soft power pin could be inverted with the extra NOR gate as necessary) Also, voltage drop from the diodes might need to be considered when selecting a diode, etc. This is a rough idea that would need to be refined for actual use.

Edit: the +5V trickle on the relay should come from the same point after the diodes on top that feed the nor gates. Considering that this trickle line runs the relay coil, that makes the optional capacitor a bit more necessary, especially if there is a delay after turning on the power supply for you to get +5V. Alternatively, you could just leave the +5V trickle on all the time and waste a minute amount of power. It's these sorts things that need testing and refining.

Edit 2: Also to be noted is that many cheap power adapters "claim" to be 5V, but actually are only that voltage under the rated load. This is a low-power application that can't exceed 5.5V (typically), so it would make sense to either find a good power adapter or get a bigger one (i.e. 9V) and bring it down to 5V with a voltage regulator (i.e. 7805).

[techknight]

I think the ADB keyboard power button is held high. momentary contact switch, pulls low when pressed. I think.... I cant remember. Heck if we wanted to, we could just simply replicate the Mac II circuit and use the PRAM batt for power like in the mac II circuit.

For my own personal use though, I am going to use a microcontroller. More expensive than logic gates, but itll fair me better. This way on systems that you cant tap a shutdown signal from, you could press-hold the power button for say 3 to 5 seconds, and it will shut off.

I guess you could implement this in logic gates as well, using a D-type latch with set/reset pins, such as the 7474. Then some type of RC time constant one-shot that while holding power button, cap discharges and flips the latch.

[Dennis Nedry]

I was under the impression that on keyboards that support the power pin, it is normally floating and closes to ground when the button is pressed - and I saw this on the IIci startup circuit at Gamba's site. This is why I drew in the pull-up resistor on it. I'm betting that with a microcontroller, there is some way to detect/decode the shut down automatically on Macs without an easy pin to tap off from. Maybe even looking at the address bus and seeing if the ROM address of the shutdown sequence is being executed. It would be:

// Init
power pin = 0; // Start with Mac off.

for(;;) // the "1 infinite loop"
{
while(adb_pin != 0); // Loop until ADB pin = 0.
power_pin = 1; // Turn on Mac.
while(address != 0x1234abcd); // Loop until this address is seen
power_pin = 0; // Turn off Mac.
}

[techknight]

I dont program in C so your over my head. I do ASM and BASIC.

Aside from that, I see what your saying. you could hook into ROM without "hooking" into ROM.

You could technically just simply decode an address thats out in a void that other hardware doesnt conflict with. A simple write to that particular address would shut the machine down, using an INIT such as bbraun's could be modified to perform such an action.

[Trash80toHP_Mini]

If I'm reading this correctly:

You could be suggesting the possibility of creating a single state logic analyzer/detector . . .
. . . such might be wedged onto a ROM SIMM V3 PCB to trip board flip-flop signal on a header pin/cable I/O line to the PSU?

The same might be done for a multipurpose MicroController based hack?

Can I use my very rusty Basic for any MicroController project?

What's an ASM? Do I need to learn that if the above is not true?

[Dennis Nedry]

You could be suggesting the possibility of creating a single state logic analyzer/detector . . .
. . . such might be wedged onto a ROM SIMM V3 PCB to trip board flip-flop signal on a header pin/cable I/O line to the PSU?

Yep, exactly. This should work in ROM, PDS and cache slots, anything with the addressing lines needed. It could be incorporated into a pass-through connector for any of these slots too.

The same might be done for a multipurpose MicroController based hack?

Yeah I suppose so. You could have a whole list of ROM addresses to look for and have different actions for each one - lights, timers, motors, It would take a pretty quick microcontroller to do this, another option is to wire up some combinational logic that looks for a specific address and stores it in a latch. This can be done with a big load of gates. You could use a small FPGA if you want to look for lots of addresses with combinational logic in one chip.

Can I use my very rusty Basic for any MicroController project?

What's an ASM? Do I need to learn that if the above is not true?

I have not programmed a microcontroller in Basic before. ASM is an abbreviation for "assembly language". This is the native language of a processor (or microcontroller), where you actually use the instruction set of a processor instead of writing statements like most other languages. Consequently, programming in ASM leaves the program dependent on the specific type of processor that it was written for. ASM can be extremely efficient and quite cool to play with but it is fairly confusing related to any other option. It is not typically a great place to start without a great deal of assistance. Programming in C or Basic has the advantage of being much easier, and easier to read, even for ASM gurus, and more portable to different processors and different developers even though the end result is often times less efficient. In practice, it is usually the best choice to avoid ASM and select a faster processor. However, if cost is critical (i.e. mass production) or you just want to play with ASM, go for it, it can be quite entertaining.

[Dennis Nedry]

You could technically just simply decode an address thats out in a void that other hardware doesnt conflict with. A simple write to that particular address would shut the machine down, using an INIT such as bbraun's could be modified to perform such an action.

Writing, reading, or executing from a particular address enables that address on the address bus. Specifying what you're doing at that address requires more logic, such as data direction and data lines. CONSEQUENTLY - every bit of ROM is read for the checksum when the Mac is turned on!! D'OH! So you can't just look for a ROM address, more logic is necessary as you have suggested.

If we are allowed to put INITs in the system, may I suggest sending a series of unusual timed pulses, a password if you will, on an available pin? You could detect those specific pulses and shut down the Mac. This would not require tapping the address lines or making near as many connections.

Also useful would be to look at the ROM code for the shutdown sequence and see if there are any clues as to how to detect it in hardware - maybe without any modifications at all.

[techknight]

What I thought about doing in this scenario, is use an ATmega128. it has a crapload of I/O pins. Tie these pins to the address and data bus, and clock the micro from the main system clock as well. (everything would be in sync then). the AVR probably doesnt have enough current to arbitrate/talk bi-directionally on the Bus, but it could simply just listen and be fine.

Have it constantly monitor the system bus for a specific write to a specific address void, As i think the bus also has a dedicated Read and Write line from the GLU. boom. power off. of course this take a million wires.

using a pulse code modulated/serial style pin toggling as you suggest would eliminate ALOT of wires/connections and work just fine. Such as using 2 Data Bits, using one as a serial clock, and the other as serial data. Bit-Bang an AA or a 55 something that simple. Or even 3 data bits and using the 3rd one as an Enable bit.

Also, I could tap into one of the serial ports at the SCC chip? just send a special command serially to the IC and poof machine shuts off. Only downside to this, it requires the serial driver to be open

Eh... Simple thing at least for the SE would be a daughterboard that sits between one of the ROM ICs and the board. Easy way to tap off the data/address bus.

[Dennis Nedry]

I don't think it will be possible to clock the microcontroller off of the Mac's CPU clock - you will probably need to go many times faster than the Mac because there is a process involved in reading and comparing the 64ish pins (32 data, <32 address, maybe others) within the microcontroller. This will take multiple cycles, reasonably 50 or so at best I'm guessing. This is why I recommended some sort of combinational logic method, such as gates + a latch, or an FPGA. This could capture the state and then you could take your time to read the captured state in the latch.

Another problem is that taking in that many bits will more than likely require multiple reads, in 8, 16, or 32 bit increments depending on the microcontroller. Even if the microcontroller is synced to the Mac's cpu clock, the address can and will change between these reads, making it impossible to even read the complete bus contents even one single time.

If you can lock up the Mac - for example, execute an instruction that jumps to itself, it will hold the address constant. Maybe that's an option somehow.

I'm a fair bit more digital than analog as we've seen lately unfortunately...

[techknight]

I didnt think about that, but you are right. But i guess it depends on the type of CPU used as far as speed ratings so a clock multiplier could be used such as the ICS511. like x4 or x8 multiplier. Then code efficiency comes in. So for slow CPUs you would need a Latch at the bare minimum i guess, especially if your looking at a single write at one address and thats it.

Or.. the FPGA approach, but I dont know the first thing about an FPGA and thats why I want to avoid it like the plague. Probably the reason they used alot of HAL/PALs back in the day. I think I have a couple of GAL16V8s but i dunno nothing about those either

[Dennis Nedry]

FPGAs are really strange and I would avoid them in any situation reasonably possible too. They can be programmed in different ways, and one way that they can be programmed is by drawing a schematic of gates, latches, flip-flops, etc and hook those up to physical pins. Then once the schematic is programmed in, the FPGA works just like the schematic - literally. FPGA stands for "field programmable gate array". That is one of the few ways that I would consider using an FPGA. They can take a load of inputs and outputs and have thousands of gates of combinational logic in between. Combinational means no clock which means asynchronous and only gate delays, no clock delays.

No matter what we use, we would fall victim to logic traps if it is not synchronous to the Mac's processor clock. Say that you jump from this address:

1000 xxxx xxxx xxxx xxxx xxxx xxxx xxxx

to this address:

1011 xxxx xxxx xxxx xxxx xxxx xxxx xxxx

And the shut down address is this:

1001 xxxx xxxx xxxx xxxx xxxx xxxx xxxx

Well, no 2 bits can change at EXACTLY the same time. So the jump must do one of 2 things to the address bus:

1000 > 1010 > 1011
or
1000 > 1001 > 1011

and through that logic trap, the latch can be triggered even though the address NEVER WAS really the shutdown address. The only way to alleviate this is to tap the Mac's processor clock and register the latch only during the proper edge of the clock.

[techknight]

Not quite understanding your logic about a trap.

[Dennis Nedry]

A quick Google did NOT turn anything up on "logic trap", so either it's obscure, my professor made up his own name for it, or I am not remembering the name correctly.

What I am referring to as a logic trap is a deep digital curiosity that causes random glitches. I'll try to explain it better.

Starting from the beginning, all combinational digital logic is made of gates, AND, OR, and NOT. Latches are when you introduce feedback into these gates, in such a way that you can lock onto something, for example, say we have a circuit with one input and one output, where the output starts as off. When an input turns on, the output turns on, but when the input turns back off, the output stays on because of feedback. (i.e. the output feeds back into an input.) So we have stored that information with the feedback. This storage is STILL combinational logic, it does not have to wait for any clock.

Sequential logic DOES wait for clocks though. So take the same example from above. If the input turns on and back off very quickly, and no clock pulse occurs during this time, it will be ignored. The input status only mattes during the clock pulse. The clock pulse registers the inputs. This has an awesome implication.

Say that you have 32 inputs. You change the inputs in between clock pulses, then once all of the inputs are settled down, a clock pulse occurs that finally registers all of the inputs. This is necessary because the EXACT time that each input changes is not known. They DO NOT and can not change perfectly simultaneously. This is why computers have clocks.

So say that you have these two binary inputs:

00

And you want to change the inputs to this:

11

Knowing that no two inputs can change simultaneously, the input state must technically change a couple of times to get from 00 to 11, even if it's in a trillionth of a second, and that can happen 1 of 2 ways:

00 -> 01 -> 11
or
00 -> 10 -> 11

If this process happens between clock pulses, then it doesn't matter. However, if you are ignoring the clock and using only combinational logic, you will occasionally detect 01 and 10 states when attempting to change directly from state 00 to 11. As you can imagine, when looking at lots and lots of bits, there can be lots of hidden intermediate states from one intended state to the next.

[techknight]

Knowing that no two inputs can change simultaneously, the input state must technically change a couple of times to get from 00 to 11, even if it's in a trillionth of a second, and that can happen 1 of 2 ways:

00 -> 01 -> 11
or
00 -> 10 -> 11

If this process happens between clock pulses, then it doesn't matter. However, if you are ignoring the clock and using only combinational logic, you will occasionally detect 01 and 10 states when attempting to change directly from state 00 to 11. As you can imagine, when looking at lots and lots of bits, there can be lots of hidden intermediate states from one intended state to the next.

Ok i knew and understood everything you have said up to this point....

What do you mean that no two inputs can change simultaneously? Thats the part I get lost at. Are you talking about the pipeline within the MCU? Reason why I ask is say you have 8 D-Flops and both are tied to a common clock latch, All inputs will latch in at the same time. +/- propagation delay. I guess the only thing that stops this from not being true is the fact that each gate could have a slightly different propagation delay from input-latch-output.