Image Map Image Map

Search:

Type: Posts; User: sergey

Page 1 of 20 1 2 3 4

Search: Search took 0.02 seconds.

  1. It is probably a good idea to have a 74*245...

    It is probably a good idea to have a 74*245 transceiver there. It will buffer/amplify the CF data bus signals. It shouldn't hurt in any case ;-)
  2. One advantage of using multiple pull-up resistors...

    One advantage of using multiple pull-up resistors on unused inputs/gates is that it makes it easier to mod the board in the future without cutting any PCB traces.
    And, actually that is also the...
  3. I found this 10 years old and very lengthy thread...

    I found this 10 years old and very lengthy thread that discusses the performance differences between CGA and VGA. It specifically refers to Alley Cat - see post #11.
  4. Replies
    6
    Views
    898

    Sorry for delay. I've sent you a PM.

    Sorry for delay. I've sent you a PM.
  5. Replies
    10
    Views
    795

    You could use a ROM disk and a battery backed up...

    You could use a ROM disk and a battery backed up SRAM disk (or potentially EEPROM or Flash ROM) as your block device.
    Is there any particular reason you want to use 8251 USART? There are better,...
  6. I remember trying that game on my Micro 8088...

    I remember trying that game on my Micro 8088 system, and I don't remember having such issues. I'll try to test it again...
  7. There are a few on eBay, although they are quite...

    There are a few on eBay, although they are quite pricey. You can also try getting a quote from https://www.utsource.net
  8. Replies
    24
    Views
    1,882

    I don't think it clears IF... Otherwise it would...

    I don't think it clears IF... Otherwise it would have to remember to restore it after the next instruction. It is handled by microcode...
  9. Replies
    24
    Views
    1,882

    Sure, you can use it.

    Sure, you can use it.
  10. Replies
    6
    Views
    898

    Just the parts cost and shipping: The ROMs price...

    Just the parts cost and shipping: The ROMs price seems to be $2 for two OTP 27C256, or about $10 for two UV EPROM 27C256. The shipping is $5 for a small USPS First Class package.
    So the total is...
  11. Replies
    6
    Views
    898

    I can burn them for you. But I am not sure I have...

    I can burn them for you. But I am not sure I have any 27256/27C256 available, I can check my parts boxes later today. If anything, local surplus store has OTP 27C256 ROMs for $1 each:...
  12. Replies
    24
    Views
    1,882

    Yes, Intel 8088 processors marked as...

    Yes, Intel 8088 processors marked as "(C)INTEL'78" have this bug. Intel processors with a later copyright year, for example "(C)INTEL '78 '81" and "(C) INTEL '78 '83" don't have it.
    I've never...
  13. Replies
    24
    Views
    1,882

    I am assuming you're talking about POP SS/MOV SS...

    I am assuming you're talking about POP SS/MOV SS bug.

    It is not a serious issue :-)
    First of all you're not using your PC clone for anything serious (I hope).
    Second, the workaround is normally...
  14. It works better?! :-) The IBM PC/XT DMA...

    It works better?! :-) The IBM PC/XT DMA implementation is horrible... Instead of using proper 8088 bus request/grant signals. DMA logic "steals" the bus from CPU by inserting wait cycles, and...
  15. Questions: What is that you're trying to do with...

    Questions:
    What is that you're trying to do with the serial card?
    How do you know the card does not work?
    What kind of serial cards? (just serial or multi I/O)?
    Can you post the photos of the...
  16. Replies
    4
    Views
    792

    Before trying to get an output on your EGA card...

    Before trying to get an output on your EGA card and composite monitor, can you test the board with something more common? CGA (you can use the composite output if you like), an known working 8-bit...
  17. Replies
    48
    Views
    4,013

    I am wondering if there is more stuff going on...

    I am wondering if there is more stuff going on behind the scenes other than MD flag change. This note particularly looks interesting (page 8-5 here):

    EMULATION NESTING
    In a native mode called by...
  18. That is AHCT... HCT is slower, about the same...

    That is AHCT... HCT is slower, about the same speed as LS



    Remember that TTL logic can't source current. So connect your LED with the cathode (-) to the logic output and the anode (+) to +5V...
  19. Your idea seems to be legit. As you've mentioned...

    Your idea seems to be legit.
    As you've mentioned accessing addresses 0x40000-0x7FFFF will access 0x40000-0x7FFFF of the SRAM and accessing addresses 0x80000-0xAFFFF will access 0x00000-0x2FFFF of...
  20. Replies
    48
    Views
    4,013

    NEC V20 and NEC V30 boot and run in x86 mode,...

    NEC V20 and NEC V30 boot and run in x86 mode, exactly as an Intel 8088/8086 would do.

    The 8080 emulation mode is enabled later on, e.g. from an MS-DOS application. That application should also...
  21. Replies
    36
    Views
    2,979

    The bus interface of 8087 is very different from...

    The bus interface of 8087 is very different from 80287. 8087 is connected in parallel to 8086/88 CPU and it monitors the CPU's instruction queue and sniffs the data bus, if it encounters an ESC...
  22. Replies
    32
    Views
    4,000

    Yeah, that QNX demo diskette was pretty cool,...

    Yeah, that QNX demo diskette was pretty cool, although it was pretty useless for any practical purposes even back in the day.

    As far as 386 goes:
    - Technically it is possible to build and use an...
  23. Replies
    16
    Views
    2,423

    8087 is NMOS and not CMOS. NMOS logic dissipate...

    8087 is NMOS and not CMOS. NMOS logic dissipate power even in a static state. This is because each NMOS gate has a pull-up resistor (typically implemented using a depletion-load transistor), that...
  24. Replies
    16
    Views
    2,423

    It is a valid concern, and it is being addressed...

    It is a valid concern, and it is being addressed by IC manufacturers. More frequent point of failure in this case is the solder joints between the IC package and the PCB (Xbox 360's Red Ring of Death...
  25. Replies
    16
    Views
    2,423

    That seems reasonable. As others mentioned, 8087...

    That seems reasonable. As others mentioned, 8087 runs fairly hot.



    8087 is built using the nMOS technology that consumes power even when idle. CMOS ICs, such as NEC V30, consume power mostly...
Results 1 to 25 of 500
Page 1 of 20 1 2 3 4