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    Nicolet 1080 (MED-80) installation

    Yes, a reader but no floppy drive on the system. Anyway, a great number of interesting tapes to read. There are two ways the NIC-80 can read tapes,depending on the reader. It can do it serially with rs232 or using the parallel bus input, depending on the reader. gnupubic, you should open the...
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    Nicolet 1080 (MED-80) installation

    You have a lot of floppy tapes but I see no floppy drive. I do have the drive and interface. I have one hard drive and interface. There are so many great tapes you have. WOW!. Your find is fantastic. I don't see the floppy DEMON, just a lot of applications. Be careful with the core memory...
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    Please take a look at my i4004 source - any improvement suggestions?

    There was one thing that you might want to include. I saw this in a printer driver code I disassemble a while back. The conditional jump instruction can be used for what I call as a SKIP instruction ( that is what I put in my disassembler ). What this is is the set the condition bits so that it...
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    Why did the Intel 4004 implement subtraction this way?

    I stand corrected. I complement both the value and the CARRY before the ADD I do not complement the CARRY when done. Extracting from my code, it is ( in Forth) Reg@ $0F XOR Carry @ 1 XOR + ACC + DUP $10 AND $10 / TO CARRY $0F AND TO ACC Dwight
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    Why did the Intel 4004 implement subtraction this way?

    If you look at the manual on bitsavers, page 30, you can see that someone made a note about the state of carry, going into the execution, that the carry was not complemented going in the operation, when showing what the operation actually did, in silicon. You are right, the carry being set is to...
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    Poly CPU and disk boards price

    On a separate subject, The Polymorphic video card has a serious timing error. I think it is funny that several others copied that error. Most displays have issues with the start of the first line ( top left ). If you have that issue it isn't something that can be easily adjusted out. It is a...
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    Poly CPU and disk boards price

    Getting the full operation of a gotek on a hard sectored disk is difficult and is not easy. There were some later soft sectored disk board from Polymorphic, for 8 inch and 5.25 inch. Still the primary drive was the hard sectored. I personally believe the hard sectored requires a track buffer...
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    KIM-1 Repairs continue

    I wonder if he pre-programmed the EEROM. For my board, there were a number of address pin swaps in order to program it from the KIM-1 as well as routing issues. ( in other words, the addresses are not 1:1 and nether are the data lines ). This would make pre-programming a little difficult as the...
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    KIM-1 Repairs continue

    I should note that Circa77 also made a regular .PLD file for the PAL. I just used the data sheet and created the file by hand. I should note that the picture on 39 had an extra wire coming off it. That was because the original PAL code had the Phase 2 clock inverted. Dwight
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    KIM-1 Repairs continue

    The post: https://forum.vcfed.org/index.php?threads/debugging-a-kim-1-computer.55589/page-2 on post 38, you can see the rats nest of my first try at the 6530 to 6532. You also see the small boards I made to go under the 6532. On the next page you can see the complete working KIM-1 with the 6532...
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    Molybdenum Disufide lubricant.

    Molybdenum grease is great. It is also really bad. Once a few year back I need to do a quick front wheel bearing grease. I new I should clean it first but I was in a hurry. I'll get to it later when I had the time. In less than a month the bear was shot. I found that mixing Moly grease with the...
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    The beginnings of my 4004 project

    Pittman's assembler isn't a particularly good assembler but it does hit just about every primary capability of the 4004 instruction set. The output isn't a particularly friendly format. It has not macro ability. It is an excellent test of a simulator. Dwight
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    The beginnings of my 4004 project

    I was looking through your commands. How do you attach RAM and I/O to your simulator. There is not a lot you can do without RAM. It should be using 4002s for the basic RAM but you can add such things as 42xx parts. The 4289 is quite useful but there are others( I used one on my Maneuver Board )...
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    The beginnings of my 4004 project

    The 4004 is actually quite fast compared to a 8080 or Z80. About 100:1 for a simulations is not all bad. Running on a current processor is what I thought you had in mind. The Pittman assembler is about the best test you can find. Dwight
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    ICOM FDOS-III for the Poly88

    I watch a damaging of the power transformer caused by a shorted electrolytic, not under my control. They do go short. Mike and I both know the ratios of failures that are typical. I've seen diodes fail without any issues with anything on the loads, like capacitors. I've even seen a ceramic...
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    ICOM FDOS-III for the Poly88

    I'm psychic or is that psycho! Dwight
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    ICOM FDOS-III for the Poly88

    It might be an electrolytic but more likely a tantalum on one of the boards. The one or more of the rectifiers is likely shorted. Don't run for too long or you'll burn the transformer. Dwight
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    Intel 4040 little or big endian?

    I don't recall but I think I did it both ways by trapping the call to the serial In/out and also trapping the serial bit changes and looking at the cycle count. Or, once the start bit, I'd set a trigger at a particular cycle count then send or receive each bit. I did the bit timing first but I...
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    Intel 4040 little or big endian?

    I have a listing file but it is not in a typical assembler format. It does include labels ( meaning less ones, like L045, for the 45th label I assigned in my disassembler ) It also does code in RPN Forth format like " 0B LDM " which in the normal assembler would be like " LDM, 11 ". My listings...
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    Intel 4040 little or big endian?

    It 's usage is described in the Users Manual. in Appendix F. The SIM4-01 schematic is on the manual pages 66 and 67. The ASR33 serial to the printer is on the upper right of 67 and uses a real 4002 output as shown in the schematic. The serial in comes in on the lower left of the schematic on...
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