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 Simple Large Computers 
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Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Compile times depend really on the I/O used, packing and unpacking would be used on character strings
only. I am assumimg ample RAM for the user programs here,none of this Kb measurement, or multi pass
compiles do to lack of space.
The protype version is just 36 bit data, and later to have two data types, word 36 bits and char 9 bits.
The FPGA PDP-4 http://fpgaretrocomputing.org/pdp4x/had used 18 bit wide memory, and I was thinking
of using the same product, but I could not find the chip was used, so I have it designed now using 8 bit parts and data types of word, and half word.
Ben.
PS: Ebay has a few but expensive.


Sun Aug 06, 2023 9:24 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
I have got the rough pcb layout of the memory card done, and it just seems to fit. Timing now to .9 uS memory cycle keeping in step with the late 70's
clock speeds. Now I need to draft out the eeprom and I/O card. I hope, to have all the schematics done around Monday.
Any advice before I send PCB's off to be made?
Ben.


Sat Aug 12, 2023 1:12 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
I now have the mother board roughed out, most of the design is frozen for the demo version of the computer.
Submitted the PCB for production.


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Tue Aug 22, 2023 7:10 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
The control logic card is roughed out, and routed. Hope to send this and the alu card card off tomorow to be made.


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Mon Aug 28, 2023 8:23 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
DON'T PRESS THE BLUE BUTTON.
Attachment:
MOMLED.jpg

OK Who did?
The mother board seems to work, now to wait for the other PCB's. Ben.


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Sat Sep 02, 2023 11:28 pm

Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1789
Very nice!


Sun Sep 03, 2023 7:47 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
The pcb's could be in tommorow. The memory/IO card has 6850 uart, RTC, Compact Flash and 32K x 36 of RAM or ROM.


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Thu Sep 07, 2023 3:47 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
The control and alu PCB's are in. Hope to have them socketed tomorrow, and stuffed the next day. Working on software and microcode first.
I hope to have the memory/Io card out mid week. Only a few parts needed from digikey. ben.


Mon Sep 11, 2023 7:34 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Attachment:
count.jpg

The front panel is not working, Patched the microcode to incrment the PC.in the idle loop.
The PC is counting so it proves some control logic and the ALU is working,
I hope to get more done when the MEMORY PCB gets installed.


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Tue Sep 12, 2023 6:28 am

Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1789
Positive progress for sure!


Tue Sep 12, 2023 12:23 pm
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