Any interest in collaborating on a REBOOT for the Apple II?

 barryhills  Oh, well, some folks are blind, others are lazy, Google Image Search revealed this image (on the right). I would use a double-pole push-button. Now you have three connections:

• Common is wired to the CPU's pin 40
• ON is wired to a 10k resistor to p5v (this keeps the pin from flopping around
• OFF is wired to ground.

You will have to, do some investigation, and trace the wire on the PCB as there may be a pull-up on pin 40 already, If there is remove the resistor. 

One word of warning.... NEVER SOLDER TO THE CPU!! I believe they were socketed. 

~~ Cris H. 

Oh BTW I also have the Programers Reference & Application manuals

let me know If you want copies there in pdf format I will have to hang them on my server. 

I am familiar with the 6502 pin definitions. The challenge has little to do with the 6502 and everything to do with the reset and power-up logic (in ROM) for the APPLE II.  I tried to make this clear.  This is an idea specifically for the Apple II. The 6502 reset simply transfers control to a routine in ROM where a multi step ridiculous flow of logic triggers various forms of soft reset and is reliant on the contents of vectors in RAM.  Dynamic Ram does not fade quickly like static ram which is why I imagine the solution will require a routine to clear memory or at least the reset vectors.

As an aside, I posted on Element 14 in search of thoughtful professionals, enthusiasts, and experts.  I never expected the very first reply to my very first post to include  snarky BS.  If I wanted snarky I would have posted on Reddit, Twitter, or Facebook.

Funny you should say "As an aside, I posted on Element 14 in search of thoughtful professionals, enthusiasts, and experts.  I never expected the very first reply to my very first post to include  snarky BS.  If I wanted snarky I would have posted on Reddit, Twitter, or Facebook." I recently had a similar experience. Eventually the real community began to respond but one of the first comments was meant to intimidate and shame me for posting. Sorry I can't help with your current project. I just thought I would help drive your other point home.

Cris is being humorous, you'd recognize it after seeing more messages over time (You can see that Cris also offered to provide you with reference manuals, it's actually a friendly response, i.e. It's easy to accidentally misinterpret the tone from text alone basically, is what I'm trying to say.

PPE_COOP's situation was actually different, people had comments on technical points solely in that case, and probably saved PPE_COOP effort and cost in patenting something (which is what they originally referred to) that wouldn't have helped them.

barryhills  Ok, I'm a little snarky, but your question centered around a manual reset of sorts, I got answers in 2 attempts from your friend Google. Your question is at best ambiguous. Yes, I have a long history with the 6800 family, but not much on the 6802, as I thought it was a bad joke, I owned the 6800 Micro Module. And I had it running in an S100 chassis, but obviously, It plugged into its own connector.  Here are two pages from the 6802 Technical Data. BTW I also have this book as well, So let me know If you want them. ~~Cris

AFTER THOUGHT: you might also play with the NMI line. I also have to modify my previous answer about a switch, If you read the spec below they claim It must be held down for some number of Clock Cycles. without bounce. ~~ 

barryhills  Ok, I'm a little snarky, but your question centered around a manual reset of sorts, I got answers in 2 attempts from your friend Google. Your question is at best ambiguous. Yes, I have a long history with the 6800 family, but not much on the 6802, as I thought it was a bad joke, I owned the 6800 Micro Module. And I had it running in an S100 chassis, but obviously, It plugged into its own connector.  Here are two pages from the 6802 Technical Data. BTW I also have this book as well, So let me know If you want them. ~~Cris

AFTER THOUGHT: you might also play with the NMI line. I also have to modify my previous answer about a switch, If you read the spec below they claim It must be held down for some number of Clock Cycles. without bounce. ~~ 

The following is a layman's explanation of the hardware problem from the perspective of the Apple II specific issues.  

Yes, NMI from an IO card interrupts the 6502 and causes a JMP to the interrupt handler in system ROM.  The interrupt handler determines which slot caused the interrupt, and yes about this time HALT is asserted....  but I am vague on who and why HALT is asserted.  In my experiments it is quite possible I did not hold HALT long enough as you suggest.  The IO card has a small amount of rom which is mapped into the memory address space available to the 6502.   The interrupt handler jumps to the program in the IO card p/rom.  IO cards in the Apple II have full access to signals for address, data, reset, halt, nmi, as well as the 2 DMA clocks for managing memory, and more.  The timing of the DMA clocks is fairly tight.  A P/ROM can sit directly on the address bus and be fast enough to play well with the timing of the DMA phases.  IO cards that need to manage DMA have generally adopted 2 different approaches to control modern Apple II IO cards; they have either used an FPGA or a PiPico.  Arduino for example is not fast enough.   FPGA is way outside my skillset.  PiPico is interesting because it's fast enough to do DMA and can easily be reprogrammed. The ONLY thing I need to do is have the 6502 execute a small program from the IO card p/rom to clear memory and JMP.  An eprom (or PiPico emulating rom) is all need plus perhaps some glue logic.  The Wildcard is a good example of how simple this should be....but I want to do MUCH less than the Wildcard (see link in this thread).  I have done enough homework to be fairly certain the hardware is a somewhat pedestrian challenge for the right person (which I am not).  Thats it for the hardware (I think).  

BUT it's what Apple did to the SOFTWARE logic (in system ROM) for reset/reboot that is the part that really annoys me and the motivation for the project.  There are several kinds of reset using different combinations of keys, not worth explaining except to say a hard reboot is not one of the options and certainly not with 1 finger.  The part that annoys me the most is that any programs is allowed to load their own reset vector into memory (DRAM) which is then used by the reset logic in system ROM.  The lore is Apple did this to prevent users from exiting a  program and to bolster copy protection.  As an aside the Wildcard works around this by taking full control of the 6502 and its memory.  This is why a simplified modern Wildcard is an appealing approach to me.  So back to hardware for a minute.  The reset vector in DRAM decays at an unpredictable (slow) rate and on PON the reset vector is frequently found to be in a corrupted state.  A subsequent attempt at one of the several reset sequences can easily send you off into never never land.  This is why one of the features of the Wildcard is EXACTLY what I want, they implemented a "clear memory and reboot" option that runs from the PROM in the Wildcard.

I know of S100 but have never owned a system with an S100 bus.  My first computer was the Apple II in 1978.  Actually not true, my first computer was a Bendix G15 acquired in 1973.  It ran in my garage for 5 years till mice made a nest out of the hand wired backplane.  I was in school during the peak S100 days and focused more on software.  

I appreciate your offer of documentation but I think I have all the documentation imaginable on the 6502 and the Apple II architecture.  But 50% of it is over my head and I certainly lack the tools to debug any significant hardware.  Especially the DMA stuff.   It may  be the case that I am making this harder than it needs to be since my proposed project ONLY is used to run a small program that clears the system DRAM then JMP to the reboot routine in system ROM.  

As for snarky, forget it.  As for being ambiguous, the original post came from the perspective of an Apple II enthusiast and some assumptions about the Element14 community so perhaps that is why parts of it seems vague.

cheers

 barryhills again Google to the rescue.  https://www.applefritter.com/content/apple-ii-hard-reset topic #3 ~~ Cris H. 

thank you.  yes, I am on that thread (twice).  The OP opted for a solution using the ROMX product.  The spirit is certainly aligned with mine but they have had issues getting the ROM code right and I believe this approach requires a different ROMX image for each different system ROM family. I think my IO card idea is a more universal solution that would drop into any Apple II.  I need to look at the ROMX based solution more deeply.  The advantage is of course the hardware is done but I would be turning a pretty nice product into a 1 trick pony in my environment.  I'd really like to ROM agnostic.