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[Lisa2]

With the recent interest in reproducing Lisa PCBs, I feel that folks here may also be interested in the learning more about the Sapient Technologies boards.   I was involved in the development of these boards and can answer questions you may have about them.  The Sapient boards are designed to directly replace the original Apple boards and include some updates and enhancements.

To start with, here is a quick overview of CPU board:

Sapient Lisa CPU - A four layer direct replacement for the Apple CPU card with the these updates:
    a) All the apple revisions have been integrated in the  design ( no bodge wires or tacked on components ).
    b) A integrated ROM switcher.  ROM switcher supports up to 8 variants (depending on EPROM size), common choices are C, D, H, 3A. Additional ROM variants could support non-parity memory, 4MB support in H ROMs, and other minor tweaks.  Also supports both Lisa and Screen mod Vid PROMS.
    c) A jumper to enable a hardware inverse video mode ( that was in Apple's original design but never used )
    d) Some support for the RamBo 4Meg mod.
    e) Mounting holes added to better secure an XLerator to reduce chance of dislocation when being moved
    f) The bare boards are 100% electrically tested (so no open or shorted traces), and some units have been built, tested, and sold, so the boards are known to work and fit.
    g) "Hard gold" plating on edge connector for durability

We are planning to sell the unpopulated PCB's soon with the cost as low as possible to cover the PCB manufacturing.  If you want one, reply to this thread.

Thank you,

Rick

[diogenes]

Hi Rick,

I have just purchased an unpopulated Sapient  Lisa CPU board from John Woodall- but my next question will be: where can I get these "special" Quarz oscillator, running not at 5MHz, but at an unusual frequency of 20.37504 MHz ? AFAIK only Lisa used this frequency- why is this necesary- can I run it with exactly 20.0000 MHz?
Next problems will be: where can I get these BOOT ROM's 4X EVEN and 4X ODD? And where can I get the Video ROM MASTER 4x ?

Thanks for any help!

Helmut

[patrick]

Lisa has an internal monitor, so you don't have to take care of any video timing. Serial communication will be 2% too slow, but this should be acceptable.

All files for the Lisa ROMs are at bitsavers.org. You only have to buy the video state PROM from vintagemicros.

[sigma7]

where can I get these "special" Quarz oscillator, running not at 5MHz, but at an unusual frequency of 20.37504 MHz ? AFAIK only Lisa used this frequency- why is this necesary- can I run it with exactly 20.0000 MHz?

Yes, as far as I know, you can use a 20 MHz oscillator. Decades ago I installed a 20 MHz crystal to repair a CPU board and AFAIK there were no issues.

I haven't figured out why Apple chose the unusual frequency... does anyone else know or have a probable explanation?

Now that there are "programmable" oscillators, some suppliers will program an oscillator to the frequency that you request, and 20.37504 MHz is no more difficult than 20.00000 MHz.

Looking at what DigiKey has today, choices for a 5V, TTL output, through hole programmable oscillator lead you to a selection of EPSON SGR-8002 parts. The board accepts both "full size" and "half size" oscillators.

Either the Standby or Enable control version will work as the control pin is grounded on that board. Either commercial or industrial temperature range is sufficient, and for this purpose 50PPM or 100PPM accuracy is irrelevant.

Picking one of the options, eg. https://www.digikey.com/en/products/detail/epson/SGR-8002DC-PTB/755251 it says it is a "value added item" which means that you should disregard the stock level of 0 as they make them to order. It says "Enter your frequency in Web Order Notes" so add something like "program SGR-8002DC to 20.37504 MHz". The programming is included in the price and is done within a day in my experience.

Note that the programmable oscillators require a special programmer (ie. not an EPROM programmer), and typically can be programmed only twice (they can't be erased and reprogrammed many times the way a UV EPROM can).

[diogenes]

Hello and many Thanks for the infomation!

Back to the unusual frequency- could it be possible that it had something to do with the US TV Colour norm-even if the Lisa has no colour capabilities, the Lisa has a Cinch connector for external Monitors. The B&W composite signal should have no colour carrier, sometimes there is one, some surveillance  VTR's need that carrier for switching the automatic recording on and off - the NTSC colour carrier is at 3.58 MHz and sometimes at 4.43 MHz- could there be a sort of  a colour trap for avoiding cross color effects?
It's only a thought, because I'm working with old open reel and cassette VTR machines and TBC's
I just found another source for a suitable Quarz oscillator:

https://centuriontech.eu/product/customized_oscillator/

Is this a good company?

[sigma7]

another source for a suitable Quarz oscillator:

https://centuriontech.eu/product/customized_oscillator/

Is this a good company?

I'm not familiar with them; there is this topic on an amiga forum:

https://eab.abime.net/showthread.php?t=111328

[sigma7]

purchased an unpopulated Sapient  Lisa CPU board...

where can I get these BOOT ROM's 4X EVEN and 4X ODD? And where can I get the Video ROM MASTER 4x ?

The Sapient Lisa CPU design has an integrated ROM switcher, which means you have the option to install larger than usual ROMs that contain multiple CPU ROM versions. eg. Rev H and 3A would be likely choices. The switches on the CPU board then facilitate switching between those versions without changing any parts.

The standard/original size of CPU EPROMs is (a pair of) 8Kx8 (2764). The ROM switcher supports EPROMs up to 64Kx8 (27512) which provides enough room for 8 versions. The video PROM socket supports a double size PROM (512x8), so two versions of the video PROM can be used (typically one would select one for rectangular pixels and the other for square pixels).

The 4X naming refers to a set of ROMs containing 4 versions. I believe the current 4X ROMs that Vintage Micros is currently putting on their assembled CPU boards contains
versions H, 3A, D, C, but I expect this may change in the future once it is established which versions are most useful.

You can install stock/original CPU Board ROMs if you wish.

Details about combining ROM images will be in a future post. Beware that when combining Video PROMs into a double size one, the two are not consecutive in the PROM.

Now corrected: (There was an error in the drawings below when they were first attached; at the bottom right it should read "SW1 On = A13 low" (not A15 low))

[patrick]

Back to the unusual frequency- could it be possible that it had something to do with the US TV Colour norm (...)

The video signal generated by the Lisa has a line frequency of 22.4 kHz and a frame frequency of 60 Hz. This is quite incompatible to both the US system M (15.734 kHz / ca 60 Hz interlaced) and the European BGI system (15.625 kHz / 50 Hz interlaced). Lisa has no color and therefore does not generate any color subcarrier.

The external video connector was hardly used in the '80s. According to Apple's documents there were two monitor types and one video projector for 22.4 kHz available from 3rd party suppliers.

[diogenes]

And can you tell me the DigiKey part # of the ROM switch? It seems to be a right angle
4 pole SPST DIP (as seen in the populated Sapient CPU board)

Thanks for any information!

[diogenes]

Is this the correct DIGI KEY part# for the DIP switch?

CT1954MST-ND

[sigma7]

And can you tell me the DigiKey part # of the ROM switch? It seems to be a right angle
4 pole SPST DIP (as seen in the populated Sapient CPU board)

There are lots of possible choices for the ROM SW, so you can choose according to your preference.

The picture shows a right angle "piano" style switch, which may be the easiest style to adjust when working on the Lisa from the rear, but other styles will work fine too.

And, if you don't install any switch, it will behave as though all poles are open, which will work fine with stock/standard/original ROMs.

Is this the correct DIGI KEY part# for the DIP switch?

CT1954MST-ND

That switch will work fine. The T suffix indicates it has tape over it for automated soldering equipment, so you'll peel that off. If the same switch was in stock without the T it might be a few cents cheaper.

That brand is a light blue colour. Other brands in stock are priced similarly and come in Black, Red, or Blue. If you have a preference, you are welcome to send me a DM and I'll help you select one.

[sigma7]

ROM switch? It seems to be a right angle 4 pole SPST DIP

A perhaps subtle detail is that switch 1 of the 4 is at the end closest to the 68K CPU.

Up on or Down on doesn't matter as long as you know which is which.

(IIRC there are right angle switches that are labelled in the opposite direction. A reverse numbered switch will work fine, you just need to be aware when setting it.)

The board also has a hole pattern for using a rotary DIP switch in lieu of the toggle/slide switch, but I don't know offhand which rotary switches would fit.

[patrick]

The EPROMs on the CPU board should have access times of 350 ns or below. However, I have also seen 3A ROMs from Sun Remarketing with 450 ns.

The video state PROM is driven by the dotclock, so it must be faster than 50 ns.

The floppy ROM is running at Apple ][ speed, so 450 ns is sufficient.

[Jon42]

I know it is probably a longshot, but worth asking anyway. Does anyone have a completed working new CPU, I/O, & Motherboard, particularly the last two? For 2/5 or even 2/10 for sale?