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Experimenting with TTL Cpu, 74LS chips, old vs New? Retro style switches?

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ebclr:
" 70s 74LS chips in the drawerer and ordering all the parts in HC/HCT format? As far as moving to the 74Axx series "

A much small power supply, and less hot.

Did you consider to use an FPGA in schematic mode? ( you can use a standard logic  TTL, but will work on FPGA tension Levels

rstofer:

--- Quote from: rwgast_lowlevellogicdesin on June 05, 2020, 07:42:50 pm ---Toggle switches like the ones on the PDP/IMASI/etc look like a huge PITA, from what I can tell you flip them in to the binary position you want and then hit a momentary store/continue button. So after that you have to manually flip them all back to 0? Using the front panel is already tedious but having to re 0 is just painful!!

--- End quote ---

Front panel toggle switches are NRZ encoded: Non-Return-To-Zero.
You set up the switches and pressed Deposit or Deposit Next and then set the next pattern, you didn't re-zero the switches.  Rinse and repeat...

And that's the way it was done back in the day.  Until the EPROM became common, it was the usual practice to toggle in a cold start loader.  That might only be a dozen instructions but would be enough to load memory from some external device - like a paper tape reader or even a disk drive.

I think the IBM PC may have been the first computer that didn't have switches and lights.  I may be off by a couple of machines but most everything into the '70s had switches and lights.

rstofer:

--- Quote from: ebclr on June 05, 2020, 10:21:54 pm ---Did you consider to use an FPGA in schematic mode? ( you can use a standard logic  TTL, but will work on FPGA tension Levels

--- End quote ---

In the Xilinx world, Vivado doesn't support schematic entry which implies a need to use the older version, ISE, but, of course, ISE doesn't support the newest chips so you're kind of stuck.  I think schematic entry is a dead issue for Xilinx.

That doesn't mean that you couldn't create HDL entities that accurately describe the functionality of discrete chips.  Then it would just be a matter of instantiating as many as are necessary and 'wiring' them together with HDL.

There could be a hybrid approach of using schematic entry on ISE, letting the tool convert the schematic to HDL and then using the HDL with Vivado.

See about half way down here: 

https://forum.digilentinc.com/topic/530-need-to-make-a-deciscion-based-on-my-back-ground-nexys-2-or-4/

duak:
Regarding the IBM PC being the first computer without switches and lighs.  The Apple II, Commodore PET and TRS-80 all preceeded the PC starting in 1977.

Motorola released their 6800 micro in 1975 with a ROM monitor in one of the system chips.  After getting an evaluation chip set, I found the bigger problem was to get or build an ASCII terminal to connect to the computer I'd built with them.

Well, you get good at flipping switches.  It is said that one gets used to hanging if you hang long enough...

jfiresto:
The LSI-11 (PDP-11/03), introduced in 1975, also had no front panel, beyond a couple switches.

EDIT: Or it might have had a third switch to control the Line Time Clock, rather than gaining it later.

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