Last visit was: Thu Oct 16, 2025 9:59 am
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It is currently Thu Oct 16, 2025 9:59 am
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BigEd
Joined: Wed Jan 09, 2013 6:54 pm Posts: 1841
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Nice!
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Tue Sep 30, 2025 6:47 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am Posts: 851
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Thank you. I got in the new 5V power supply and it is 50% bigger than the old one, and POWER to spare. Testing now a .750 uS clock cycle.
Ordered parts for a .650 uS clock cycle, the design limit for this computer. This includes bigger bypass caps. Now In the ballpark of PDP-8 memory speed here. Most of my time will be now on software and mico-code revision. I want to see if I can do simple 36 bit design and that means limited character operations. The current design was designed more for Small C.
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Sat Oct 04, 2025 3:27 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am Posts: 851
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oldben wrote: Thank you. I got in the new 5V power supply and it is 50% bigger than the old one, and POWER to spare. Testing now a .750 uS clock cycle.
Ordered parts for a .650 uS clock cycle, the design limit for this computer. This includes bigger bypass caps. Now In the ballpark of PDP-8 memory speed here. Most of my time will be now on software and mico-code revision. I want to see if I can do simple 36 bit design and that means limited character operations. The current design was designed more for Small C. Things have got too messy,so I need to start fresh. A 1.00 uS clock or .868 uS clock is planned. I am short a few 16 pin sockets so I plan to chop down some 20 pin sockets. This will keep me busy over the week end, as I build new pcb's,
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Fri Oct 10, 2025 4:39 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am Posts: 851
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I found some lose 16 pin sockets, so I got the cpu board made. Timing is .918 uS, for a 1.8 uS emulation. Faster may not work, so need more testing. .833 uS is the next trial. Revised the order code to have ,Read Switch Register, and made the PC (p) a valid register for load. Added base registers E..L, load store only, giving more a 1960's feel. It may not compete with the PDP 11, but it does compete well the IBM 1130.
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Sat Oct 11, 2025 6:25 pm |
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oldben
Joined: Mon Oct 07, 2019 2:41 am Posts: 851
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A plcc socket cracked, so that PCB is toast.Testing using the other hacked PCB. Gone to 4.77 Mhz, for PC speeds  This build seems stable so far.
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Mon Oct 13, 2025 10:02 pm |
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oldben
Joined: Mon Oct 07, 2019 2:41 am Posts: 851
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Found a 4.9Mhz oscillator, in my junk box and now testing with that. Removed the pc as valid destination. The irq service call, now jams 007000,2 into the IR, and state counter,permitting a push of the pc on the stack,
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Wed Oct 15, 2025 8:35 am |
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