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2022.06.03 added links to LisaList1 and LisaFAQ to the General Category

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 11 
 on: November 09, 2022, 11:19:57 am 
Started by turbodiesel75 - Last post by stepleton
Your profile says you're in Orlando, so people in the USA only I assume?  :)

 12 
 on: November 09, 2022, 10:56:55 am 
Started by turbodiesel75 - Last post by turbodiesel75
Anyone here willing to do a refurb/recap on my 1.2A power supply for Lisa 2/5 (for a fee, obvi)?

 13 
 on: November 04, 2022, 02:34:55 pm 
Started by stepleton - Last post by compu_85
The BBC uploaded a copy of this, and it looks to be higher resolution.

https://youtu.be/OfGJn3oI6sA

I wonder if any of the Quantel PaintBox crowd has details on what made this work?

-J

 14 
 on: October 29, 2022, 11:45:12 pm 
Started by rayarachelian - Last post by Lisa2
I think this is the pinout for J18...
it would be wise to verify for yourself of course.
James,
I did check the PCB and those are the correct pinouts.
Thanks,
Rick

 15 
 on: October 29, 2022, 02:20:49 pm 
Started by rayarachelian - Last post by rayarachelian
Excellent, thank you!

Edit: Actually, you've put up a line for the DOTCLK there, that's a good point I've missed with this project idea, if there's a clock to time off of, it's well worth using it (perhaps with a counter to divide it down as needed.)

 16 
 on: October 28, 2022, 11:57:18 pm 
Started by rayarachelian - Last post by sigma7
I think this is the pinout for J18...

 1   DOTCLK (pin 106 of CPU board)
 2   Ground
 3   /HSYNC (pin 111 of CPU board)
 4   Ground
 5   /CSYNC (pin 67 of CPU board)
 6   +5
 7   VID (pin 115 of CPU board)
 8   +5
 9   /VSYNC (pin 113 of CPU board)
10   +12

If you are going to attach to it, it would be wise to verify for yourself of course.

 17 
 on: October 27, 2022, 06:09:51 am 
Started by rayarachelian - Last post by rayarachelian
To facilitate making an adapter for this, the Sapient motherboards have a header position beside the CPU board that has video signals and power.
I just happen to have Sapient motherboard next to me, here is photo of the connector (J18) that was added to the design for this very purpose. 
Rick


That's most excellent, can you share the pinouts to that connector so that someone who wants to make use of it knows which pins do what?

 18 
 on: October 26, 2022, 09:58:14 pm 
Started by rayarachelian - Last post by Lisa2
To facilitate making an adapter for this, the Sapient motherboards have a header position beside the CPU board that has video signals and power.
I just happen to have Sapient motherboard next to me, here is photo of the connector (J18) that was added to the design for this very purpose. 
Rick

 19 
 on: October 26, 2022, 05:54:52 pm 
Started by rayarachelian - Last post by sigma7
From time to time the issue of replacing the CRT with an LCD has come up. Until recently, the available resolutions of LCDs weren't sufficient to render an accurate representation of the rectangular pixels of the stock Lisa video.

Various online references to the Lisa rectangular pixels say they are 50% higher than wide. ie. a H:W ratio of 3:2. If that were the case, then using an array of 3x2 LCD pixels per Lisa pixel would require 1092 x 1440.

I wondered what this would look like on a 1200x1920 monitor so I made a graphic rectangle that size. Seems like a reasonable size to look at in spite of the big border, but surprise, it doesn't look right!

The actual size of the physical image the Lisa is supposed to have on screen is defined by an Apple service part #077-8043-A, which is a graticule overlay. I've never seen one and I haven't been able to find any documents as to its measurements.

Next best I can do is to measure the opening in the front panel, and to me it looks like an image of 6" x 9" would fit nicely. (Hmmm... 2:3 ratio)

720 pixels in 9" is 0.01250" per pixel
364 pixels in 6" is 0.01648" per pixel

and  0.01648 : 0.01250 is a ratio of 1.318, not 1.5

If the specification of a Lisa pixel is actually a ratio of 4:3 then given
720 pixels in 9" is 0.01250" per pixel (width)
364 pixels at 4:3 would be 0.01667" per pixel (height) and that would result in the raster being 6.0667" high.

So I believe the correct description of the Lisa video is a H:W ratio of 2:3 for the entire raster, with each pixel being a rectangle of 4:3 H:W

It does make an LCD more challenging as it would require a HxW resolution of 1456 x 2160, but this will fit in now available 4K monitors.

To facilitate making an adapter for this, the Sapient motherboards have a header position beside the CPU board that has video signals and power.

James

edit1: fixed pixel's aspect ratio -- it is taller than it is wide
edit2: fixed math and rewrote to be consistently H:W

 20 
 on: October 26, 2022, 04:29:47 pm 
Started by rayarachelian - Last post by rayarachelian
The PiStorm project is a Raspberry Pi 3A (or 3B with riser) with an FPGA attached to the GPIO pins, which directly replaces the M68000 CPU, it has been used in a Mac SE as well as originally various Amiga models.
It does not work with Lisa hardware, likely because the FC0, FC1, FC2 lines are not accessible from the PiStorm. It's possible that just either grounding FC2 (supervisor mode) or tying it to +5V will make it work, if not perhaps FC0 or FC1 would need to be pulsed properly.

It runs an emulator on the RPi itself, but the more interesting bit is that it can be used to directly access the Lisa's hardware. This can allow us to use the Lisa's hardware as a terminal. i.e. CRT+keyboard+mouse, and possibly all the I/O ports and expansion slots from Linux on the Pi, if we build a bunch of device drivers that Linux understands.
So first thing that's needed to be written is a memory driver similar to /dev/mem to allow random access to the Lisa's hardware memory I/O - this would be set to 2MB or so. Next, we'll need to initialize this driver by setting the Lisa's MMU to map all memory, including I/O space the same way as the "H" ROM does, but then set the video page memory to a fixed address, as low as possible.  (We can even download the Lisa Boot ROM from the Lisa's memory space and use it for the emulator later.)

Next we'll need to write several drivers, one of the Lisa Frame Buffer, but on the Linux side ofc, same for the keyboard, and mouse. We could also add drivers for the Z8530 and possibly VIA6522s to allow access to printers/ProFile hard drives, a floppy driver, etc.
Next we'll need to set up X11 to mirror from the RPI's HDMI output and the Lisa's 1 bit output.
This will allow us to use the RPi in the Lisa and access the desktop/etc. You could then use the Lisa's hardware as a console for Linux, and run whatever software, even "abominations" such as DOSBox, etc.
The RPi's sound output could be connected with an amplifier to the Lisa's sound output, likely on the I/O board, though there's a SPKR line on the expansion slots that could also be used. Or, sound could be snaked out the back to a pair of amplified speakers. I'd also use low profile USB and ethernet extenders to come out of the back of the Lisa. These are important to remote control the RPi incase of issues, but also, to allow you to use a standard USB keyboard and mouse incase your Lisa doesn't have working keyboards, etc.

LisaEm will need to be started in Kiosk mode with raw video, and also modified to allow you to use passthrough for I/O. Passthrough for I/O will allow LisaEm to reroute memory access to some device, say the Z8530 directly the hardware Z8530, and same thing for various expansion slots, etc. as the user decides. Otherwise devices such as the floppy or ProFile hard drives can be virtualized and disk images used from the SDXC card slot on the RPi3.
We also need some way to detect IRQs, not sure if the PiStorm allows for that at this time, but that might not be a blocker if we don't allow passthrough I/O and use polling to see if a device needs attention.

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