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Ultra 1 uses a funky serial port pinout?

Discussion in 'Sun Hardware' started by Michael Brown, Apr 26, 2006.

  1. I'm trying to get my Ultra 1 working (installing Debian, so that I can build
    a Linux image for my JavaStation), and have run into an annoying problem.
    First of all, the Ultra 1 really dislikes my cgsix - the picture is
    completely unstable (using a GDM20E20), despite it working fin on my Ultra
    2. So, the alternative was to use the serial port. This is where things get
    odd ... I can *send* commands fine to the U1. However, nothing ever gets
    sent back. Again, using an identical setup with the U2 results in everything
    working fine. I'm using a DB25->DB9 converter with a DB9-DB9 null modem
    cable to an x86 PC. I'm guessing that the U1 is doing something slightly odd
    with the serial port, but really have no idea where to start. Any hints?
    Michael Brown, Apr 26, 2006
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  2. I've never had any problems with any of my Ultra 1s on the serial
    port. I'm a pretty heavy serial port user, seeing as my main focus is
    router & firewall configuration, which mostly happen over a serial connection.

    Sounds like a bad Ultra 1. Their DB25 serial ports are very standard.
    I've never had problems with a CG6 driving video out one either,
    although upgrading to 1e with a Creator 3D is a world of difference :)

    If you really want to troubleshoot, a RS-232 break-out box is the best
    place to start, you can see if the lines are driven correctly, see
    data come across as the LEDs flicker, etc.
    Doug McIntyre, Apr 26, 2006
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  3. So you're typing blind and it seems to work?
    No oddities.

    Although rare, I have seen a few machines that appeared to have a single
    pin failure of the serial connection (either send or receive was dead).
    Darren Dunham, Apr 26, 2006
  4. Hi,

    Could it be that the Ultra 1 is set to use RS422?

    Michael Laajanen, Apr 26, 2006
  5. AFAIK RS-422 has never been available on the standard Sun
    systems. Some has been configurable to use either RS-423 or RS-232,
    and it is mainly the voltage the differs. Both are single ended, as
    opposed to the balanced RS-422.

    Apple used RS-422 in their serial ports, which made ordinary serial
    cables slightly more complex.

    Although relatively uncommon, I have actually suffered from broken
    serial ports on two U2 system boards, which use a similar design as
    the U1.
    Thomas Tornblom, Apr 26, 2006
  6. Yup. Same thing happens on both ports (A and B), which is what makes me
    suspect some sort of incompatibility thing is going on. Almost like the Sun
    doesn't recognise the handshaking and thinks that the other computer isn't
    ready. It's strange that it works fine on the U2 though.
    Port A or B not working correctly would seem to be a pin failure, but both
    ports failing in the same way seems a little too much of a coincidence ... I
    might try making my own DB25-DB25 null modem cable from the link and connect
    up the two Ultras to see if that helps.
    Michael Brown, Apr 27, 2006
  7. I had a 1E a couple years ago ... it died completely (absolutely nothing
    woks any more ... PSU is dead, HDD spins up but no response, RAM is fried,
    SBus cards dead). My guess is a complete PSU failure that pumped 240V into
    the system or something.

    Incidentally, I figured out what was wrong with the cg6. The monitor has
    died. I think it was one of those situations where it was on the verge of
    dying, but the motion of moving it between the computers was enough to bump
    whatever connection that was loose back into place (until it was moved
    again). I'm getting the same sync problems on my U2 with a C3D, and I know
    that was working fine at some point. I might open up the monitor and have a
    bit of a look to see if there's anything obviously wrong ... not quite sure
    how to get rid of something this big :)
    Yeah, I might try tracking down someone who has one. Alternatively, I nearly
    got Debian working last night by installing using the keyboard and monitor.
    The picture (well, the top half, since the bottom half goes off the bottom
    of the screen) is sometimes stable for one frame, so I pointed a digital
    camera at the screen and kept on taking photos until I got lucky and could
    read what it was asking. Unfortunately, it doesn't want to boot up off the
    HDD (device times out or somesuch). Once I can get a basic system installed
    I'll just sort it out through SSH.
    Michael Brown, Apr 27, 2006
  8. I had a look just now, and the jumpers appear to be set for RS-232. I've
    stop-N'd a few times as well which should hopefully have got out any past
    configuration wierdness.
    Did both ports fail in the same way, or only one port?
    Michael Brown, Apr 27, 2006
  9. On a hunch, I swapped the U1 to do RS423 (instead of RS232, just a voltage
    change). Everything works fine now. So much for PCs having RS232 ports!
    Michael Brown, Apr 27, 2006
  10. On both it was just one of the ports, and my guess is that it was the
    line interface chips, not the uart. They probably failed from abuse,
    connecting stuff with power on that were at different potential.
    Thomas Tornblom, Apr 27, 2006
  11. Michael Brown

    Greg Andrews Guest

    There is no such setting on the Ultra 1.

    Greg Andrews, Apr 27, 2006
  12. Michael Brown

    Sunny Guest

    PCs most definitely have RS232 ports. Some will work at the lower
    voltages specified by RS423, but most won't.

    I suspect the U1s jumper is incorrectly or confusingly labelled, and you
    actually switched it from RS423 to RS232.

    Sunny, Apr 28, 2006
  13. I'm not sure about the Tx pin, but the the RTS pin went from 10.something
    volts to 5.60 volts, so I'm pretty sure it's running in RS423 mode at the
    moment. The PC is running in RS232 mode, as it's putting out 10.58 on RTS.
    Somehow, the two are managing to talk to each other despite not managing to
    talk when the sun is in RS232 mode. Ahh, the joys of computers ...
    Michael Brown, Apr 28, 2006
  14. Michael Brown

    DoN. Nichols Guest

    It sounds as though you need to change some eeprom settings, or
    to force some handshake pins true. Take a look at the following entries
    (from an Ultra-1 which I have):


    I think that you need to set your ttya-ignore-cd to true, and
    perhaps ttya-rts-dtr-off to true as well, so it will do no handshaking.
    This may mean that it will overrun a slow terminal if there is a lot to
    display, but you should at least get things done.

    On earlier systems, it was often necessary to hardwire the CD
    and DTR pins true -- or at least one of them.

    Nothing that I am currently running, not even the ancient LX, is
    old enough to lack those EEPROM options.

    With the ignore-cd setting false, it won't send anything to your
    terminal until it sees the CD pin true. (It thinks that it is talking
    to a modem, and wants the CD to tell it that the supposed modem is
    connected to something at the other end.

    You should be able to set these using the eeprom command (at
    least from a booted Sun OS, or from OpenBSD (that I know for sure), or
    from the OPENboot level, using the printenv and setenv commands.

    Good luck
    DoN. Nichols, Apr 29, 2006
  15. Michael Brown

    Greg Andrews Guest

    Did you switch the jumpers back to confirm that they fail to communicate
    when the Ultra's jumpers are at the RS232 voltage setting?

    Greg Andrews, Apr 29, 2006
  16. Michael Brown

    Trinean Guest

    Could it be that the Ultra 1 is set to use RS422?
    Sure there is, or rather RS423. In fact RS423 is the default!

    According to the jumper chart J2104 and J2105 on the system board controls
    whether it is RS232 or RS423.

    Trinean, Apr 30, 2006
  17. Michael Brown

    Greg Andrews Guest

    As a previous post in this thread explained, there is an enormous
    difference between RS423 (which the Ultra's jumpers can select)
    and RS422 (which they cannot).

    Greg Andrews, May 6, 2006
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