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discrete CRT character vector generator? Maybe Tek style?

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Martinn:
Hi all,
for my discrete CPU idea which is simmering on low fire I still need a display and a CRT would fit perfectly (I even have an almost working scope clock design, so CRT control is done).
But how do you generate text on a CRT using discrete components only (not using VHDL/FPGA or a microcontroller, which would be the trivial option)?

Two designs from the relevant era (around 1965?) come to mind:
The CDC 6600 is a discrete supercomputer with vector CRT display. Schematic is in here http://www.bitsavers.org/pdf/cdc/cyber/cyber_70/fieldEngr/60125000C_6602_6603_6622_6681_6682_Data_Channel_Diagrams_Dec65.pdf starting from page 5.
Not sure about the IBM System/360, which was also fully discrete.

And (probably more known on this part of the forum) there is the Tektronix 7000 series readout. It is described here https://w140.com/tekwiki/wiki/7000_series_readout_system
with the key component being an analog ROM (designed by Barry Gilbert), schematic https://w140.com/tekwiki/images/d/d9/Tek_155-0023-00_155-0024-00_155-0025-00_155-0026-00_155-0027-00.pdf
I find this quite elegant as it solves both the coordinate storage and the transition or vector generation - fully analog (the LeCroy orange CRT scopes used analog integrators for vector generation, but the rest was fully digital (68000 IIRC)).

Unfortunately I have neither a supercomputer design budget (or team) nor access to a foundry making full custom chip designs. What I do have (and Seymour Cray or Barry Gilbert didn't have) is the JLCPCB assembly service, which let's me order a PCBA with a few thousand SMT components without going bankrupt. Unfortunately chip design specials as for example Gilbert's multi emitter transistors (mask programmed) for the analog character ROMs are not easily replicated with discrete components (I'll give that a try though).

Any other idea how I could tackle character generation?

As a side note: Looking back, in these times (1960s) there seemed to be many "celebrity" designers - Shockley, Gilbert, Wilson, Cray, Widlar... If I would have to name a famous designer of the past few decades, I would not know a single one. Are there none or do I just not know them? Maybe today's technology has gotten that complex that no single genius could achieve something worth mentioning (thing of the monstrously complex EUV steppers)?

- Martin

cantata.tech:

--- Quote from: Martinn on January 29, 2023, 04:08:54 pm ---Any other idea how I could tackle character generation?

--- End quote ---

In software ?

Have a character output buffer, [w,h,c] (width * height * sizeof(colorinf)) and a font table.

Generate scan lines by reading the buffer and working out the bit pattern for each character then buffer line.

Send that to the next output stage.

I have the cutest Sony TV 501 from the 1970's that I bought in Japan that would love something like this so I'm keeping an eye on this thread.

Martinn:

--- Quote from: cantata.tech on January 29, 2023, 04:21:41 pm ---In software ?

--- End quote ---
Of course, this would be easy. But as I wrote the question was

--- Quote from: Martinn on January 29, 2023, 04:08:54 pm ---But how do you generate text on a CRT using discrete components only (not using VHDL/FPGA or a microcontroller, which would be the trivial option)?

--- End quote ---

cantata.tech:

--- Quote from: Martinn on January 29, 2023, 04:27:55 pm ---
--- Quote from: cantata.tech on January 29, 2023, 04:21:41 pm ---In software ?

--- End quote ---
Of course, this would be easy. But as I wrote the question was

--- Quote from: Martinn on January 29, 2023, 04:08:54 pm ---But how do you generate text on a CRT using discrete components only (not using VHDL/FPGA or a microcontroller, which would be the trivial option)?

--- End quote ---

--- End quote ---

Use 74* series discrete components https://en.wikipedia.org/wiki/7400-series_integrated_circuits , but the process that I described would most likely be the same.

If you have some plan to do something that isn't based on any digital components and uses analog only then of course that will be interesting to hear about.

Martinn:

--- Quote from: cantata.tech on January 29, 2023, 04:52:13 pm ---Use 74* series discrete components, but the process that I described would most likely be the same.

--- End quote ---
Discrete means transistors, resistors, capacitors, inductors. 74xx are integrated circuits - the opposite of "discrete"


--- Quote from: cantata.tech on January 29, 2023, 04:52:13 pm ---If you have some plan to do something that isn't based on any digital components then I'm happy to listen to your plan.

--- End quote ---
This formulation is a little vague.
CDC 6600 or System/360 were supercomputers (=digital) built from individual transistors (or hybrids in the IBM case).

But have a look at the 7000 readout (linked above) - although it uses a lot of integrated circuits, core concepts like the analog ROM are fully analog.

The reason why I am looking at a discrete design ist just for the challenge - as I wrote it would be simple and straightforward to do this an a microcontroller (just go through a display list via IRQ) or FPGA (which would be more fun).

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