General Category > LisaList2
Really super weird things about the Lisa
jamesdenton:
--- Quote from: rayarachelian on July 05, 2019, 11:35:11 am ---It seems that the Lisa's expansion slots use 56 pin ZIF sockets, but Apple - at least on the 2/10 motherboard, not sure about the 2/5 which I don't have infront of me right now, could accommodate upto a 64 pin socket. Wonder what plans they might have had for those extra pins? I don't think those are wired at all though.
(Weirdly it's labeled 63, while the existing one ends at 56, not sure why the odd end, so possibly one pin was missing on 64 pin ZIF connectors?)
--- End quote ---
If you look at some of the early/prototype cards, they have more than 56 pins:
- Lisa color board prototype https://www.computerhistory.org/collections/catalog/102673915 (sorta)
- Priam Interface Board https://www.computerhistory.org/collections/catalog/102673924
I'm really interested in this:
- 3-port parallel card https://www.computerhistory.org/collections/catalog/102673920
I seem to recall in those UniPlus sources talk of "Up to 10 hard drives". I assume they meant 1 internal and 3x3 externals.
The CHM has some great examples and pics online.
rayarachelian:
--- Quote ---
If you look at some of the early/prototype cards, they have more than 56 pins:
- Lisa color board prototype https://www.computerhistory.org/collections/catalog/102673915 (sorta)
- Priam Interface Board https://www.computerhistory.org/collections/catalog/102673924
I'm really interested in this:
- 3-port parallel card https://www.computerhistory.org/collections/catalog/102673920
I seem to recall in those UniPlus sources talk of "Up to 10 hard drives". I assume they meant 1 internal and 3x3 externals.
The CHM has some great examples and pics online.
--- End quote ---
Those are very interesting, hope their schematics and ROMs make their way to bitsavers.
That color board is really interesting, but from the picture the only thing I can guess is that it has a lot of RAM chips on it, some resistor packs, a crystal, and it has probably 3 RCA or Coax connectors, but hard to tell what else, so possibly sync-on-green or CVBS. From the looks of it, all the extra pins are shorted out - at least on the component side - so wonder what that hints at. I'm guessing that this is something like a 320x240 color frame buffer. The interesting bits would the ROM it has - if any, and ofc any driver/app software for it. Would be really neat to see this in action.
That Priam card does seem to have used the extra pins. Weirdly, it doesn't seem to use a discrete VIA chip but rather lots of smaller logic chips and is labeled high speed parallel and Apple. So possibly, Apple meant to have used it for other devices.
This is really a great read: http://bitsavers.org/pdf/apple/lisa/Whopper_ERS_V2.0_Jul83.pdf this would have been the Lisa 3 or maybe it predates the 2/10, but sadly not in color, though, it would have had switchable square vs rectangular pixels, though I'm sure that transition, since it would be in hardware, would be really annoying to the end user. It would also use a 10MHz 68010 which would support an MMU fully, though it would have slightly less RAM. Interestingly on PDF page 27 we see the Whopper's mouse does support 3 buttons.
The 3 port parallel could be rebuilt without too much trouble from the existing schematic of the 2 port card if we can figure out the I/O address of that 3rd VIA, which likely can be found. Not sure if LOS will immediately recognize it or if its drivers need changing.
There is mention of a 4 port card here: http://bitsavers.org/pdf/apple/lisa/IO_Slot_Cards_Jul84.pdfbut it doesn't say if it's a parallel or the Tecmar, I suspect this is a parallel port card. Interestingly, the AppleNet card has an ID of 1 and the Lisa's serial # contains an AppleNet ID, so it's likely the AppleNet card was the very first one. But then what's ID 3 "Profile card"? (From what James MacPhail mentioned previously about the Tecmar card, it doesn't have an actual ROM ID)
Too bad the images are in such low resolution.
So looking at that motherboard with the extra pins, it's a 2/10 motherboard, a Lisa 2/5 mother board I have does not have them and the PCB ends immediately at the end of the ZIF socket. So somewhere there's likely a prototype board with "63" pin expansion port slots.
Relevant to the broader discussion in http://bitsavers.org/pdf/apple/lisa/hardware/Lisa_Hardware_Reference_Manual_Jul81.pdfwe find a few interesting bits:
* On PDF page 17 we can see the status register, which on bit 6 and 7 the serial number is mentioned.
* On PDF page 34 the mouse pinouts are mentioned, pin 6 is N/C likely this would have been SW2, and pin 7 is "switch 0 always grounded" - this would have been right click.
* On PDF page 38 there's mention of a CVSD sound chip which never made to the Lisa, too bad, this would have been great.In http://bitsavers.org/pdf/apple/lisa/hardware/Lisa_Hardware_Manual_Sep82.pdfwe find:
* PDF page 64 - the mention of the serial number is removed (although obviously it's still there in the hardware)
* PDF page 125 - a discussion of the video circuitry and state machine
stepleton:
--- Quote from: rayarachelian on July 05, 2019, 09:30:07 am ---I'm afraid McDuck will have to keep swimming in his vault of gold coin with beard stubble.
No, it's not part of the video board, (the video board is all analog) it's part of the CPU board and the VSROM on there is socketed.
--- End quote ---
Oh man, that's a primo head-smacker. I once knew that! I'm spending too much time with other systems these days...
I still think it's hard to bet against some half-hearted cost-driven kludge.
They might not have put it in the COP421 since I think that was mask-programmed for them over at NatSemi. As for why not the I/O or CPU ROMs, I'm not so sure, but maybe the machines they used to initialise those were also used for other Apple ROMs and they didn't want to introduce a new process. The video state ROM is pretty small, I thought---a few hundred bytes? Maybe in 198x it was easier (i.e. cheaper) to get serialised ROMs when the ROMs were tiny.
To follow you away from the video stuff---ISTR from my AppleNet beeping that the expansion bus wants you to express full addresses by latching N of the address bits into some register on the CPU board and then putting the remaining bits onto the bus. Maybe the extra 8 pins come from a time before they committed to this latching scheme, when they expected you to put more of the address onto the bus than they did later on? I think 8 more address lines on the expansion card (so going from pins 0-55 to 0-63) could get you a full 2MB of address space, which if I recall correctly is the maximum the Lisa can support (thanks to its MMU design). Then again, it looks like the bus connector could have twelve additional pins, so it seems like it ought to be counting up to 67 or 68?
--Tom
patrick:
--- Quote from: rayarachelian on July 05, 2019, 10:53:07 am ---Most likely nothing will happen. But it would be an interesting experiment to see what codes the COP421 produces when these extra two mouse buttons are triggered, if any. (It may well be that while the hardware is still there that Apple removed the code from the COP421, in which case, you could never take advantage of the extra buttons.)
--- End quote ---
If someone wants to investigate this in detail: here is the COP421-HZT ROM code: http://bitsavers.org/bits/Apple/Lisa/firmware/COP421-HZT_LisaIO.zip
To test modified COP firmware in your Lisa, you will have to obtain a ROMless COP402 and wire a circuit like this: http://john.ccac.rwth-aachen.de:8000/patrick/COPSreader.htm#emulator
Patrick
BTW: The Lisa Motor COP421-KPK is in the Widget firmware section http://bitsavers.org/pdf/apple/disk/widget/firmware/. The three letter code indicates the ROM mask.
sigma7:
--- Quote from: rayarachelian on July 05, 2019, 11:35:11 am ---It seems that the Lisa's expansion slots use 56 pin ZIF sockets, but Apple - at least on the 2/10 motherboard could accommodate up to a 64 pin socket. Wonder what plans they might have had for those extra pins?
--- End quote ---
The 1/5 Motherboard doesn't have those extra pins.
On the 2/10, they are all connected to +5V or ground. I think it is unlikely they were added for EMI reduction, so my guess is they were added with an expectation of greater power requirements or perhaps in anticipation of a new machine having more signals on the larger connector. Having these in the 2/10 would allow new larger expansion boards to be backwards compatible with the 2/10. However, since the larger connectors were not actually installed on the 2/10 motherboards, I presume the plan was scrapped.
Another option is that the size of ZIF used was to be discontinued and they would need to use a larger one if production continued, and thought they might as well use the pins. That's pure speculation, but finding these particular ZIF sockets is challenging.
--- Quote ---I've had the yellow plastic that rotates with the pin on a couple of my motherboard break off a bit, it didn't affect the slot, but it seems these are starting to age.
--- End quote ---
I've had quite a few of the yellow cams break as well. Closing the ZIF gently while making sure the card is aligned minimizes the risk. I hope to 3D Print replacements some day.
--- Quote ---Yet, another weird thing, since the Lisa uses the MC68000 MOVEP opcode to do I/O, even though the Lisa's expansion slots are capable of doing 16 bit I/O all the expansion slot cards I've seen are all 8 bit. Further adding to the weirdness, in fact, the ROMs on these are all 8 bit, and the boot ROM copies them to RAM before executing the code on them! I wonder if they ever even had a 16 bit slot?
--- End quote ---
The byte-wide ROM code is copied to RAM as the 68000 always makes word (double byte) fetches when executing instructions; ie. it can't run code from an 8 bit source. (IIRC, the 68020 and up have signals that report the word size of the address accessed so could run code supplied over an 8 bit buss.)
The LSAC (Lisa SCSI Accessories Card) had a second ROM socket connected to the other byte, so it could run code from ROM. We never used the additional socket except for development.
The Priam card uses both bytes for faster data transfer in the Lisa. It appears the LisaDAC sound card and the I/O test card also use both bytes.
Some cards have the ROM connected to one byte and the I/O connected to the other; eg. the SCSI card.
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