16550, PS/2 m55sx and OS/2 6.167f?

16550, PS/2 m55sx and OS/2 6.167f?

Post by Gary Hennig » Tue, 11 Feb 1992 02:02:00



First I guess I should ask if anyone knows for sure that the PS/2 Model 55sx
has a 16550 UART in it's serial port. My understanding was that all PS/2's
including and above the Model 50 had a 16550 built in. If this is true why
doesn't OS/2 recognize it? I do:
                MODE COM1:BUFFER=ON
                        or
                MODE COM1:ENHANCED=ON
and OS/2 tells me that both BUFFER= and ENHANCED= are invalid for my serial
device! I think I remember reading that the first 16550's had some
problems, is there a way to distinguish the bad 16550's from the good ones?
Has anyone else gotten their m55sx to use the 16550? If it is indeed a bad
16550 will IBM replace it? I've had the machine for about 1.5 years so the
warranty is no longer there.

Any info greatly appreciated,
--
Gary Hennigan
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=++=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
+= PhD Student, Computational Electromagnetics  | Member: Utilitarian  +=
+= New Mexico State University                  | .signature club      +=
+= Phone: (505)646-4808                          ----------------------+=

 
 
 

16550, PS/2 m55sx and OS/2 6.167f?

Post by Jeff Altm » Thu, 13 Feb 1992 05:37:48



>First I guess I should ask if anyone knows for sure that the PS/2 Model 55sx
>has a 16550 UART in it's serial port. My understanding was that all PS/2's
>including and above the Model 50 had a 16550 built in.

The first 4 months or so of 55sx's have original 16550 not 16550A[NF]
implementations.  The 16550 contained a defective buffer and would not
switch into FIFO mode.

Quote:>I think I remember reading that the first 16550's had some
>problems, is there a way to distinguish the bad 16550's from the good ones?
>Has anyone else gotten their m55sx to use the 16550?

HAven't been able to try because 1.167f will not work with my SCSI drive.

Quote:>If it is indeed a bad
>16550 will IBM replace it? I've had the machine for about 1.5 years so the
>warranty is no longer there.

I am an IBM Technical Advisor.  As such I am supposed to be provided with
direct service info from IBM.  When I inquired about this with IBM National
Dealer Support I was told that IBM did not consider the use of a 16550 instead
of the 16550ANF a defect, even though the FIFO did not work.  Therefore,
IBM would not replace the planar board for FREE.  The cost was somewhere over
$400 if I wanted to send mine in for a swap.  Two to three weeks with shipping
time.

And no, it is not possible to replace the chip yourself.

>Any info greatly appreciated,
>--
>Gary Hennigan
>+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=++=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
>+= PhD Student, Computational Electromagnetics  | Member: Utilitarian  +=
>+= New Mexico State University                  | .signature club      +=
>+= Phone: (505)646-4808                          ----------------------+=


--
- Jeff  | Altmania Productions     |================================|




 
 
 

16550, PS/2 m55sx and OS/2 6.167f?

Post by Jason Campbe » Thu, 13 Feb 1992 11:16:12




>>First I guess I should ask if anyone knows for sure that the PS/2 Model 55sx
>>has a 16550 UART in it's serial port. My understanding was that all PS/2's
>>including and above the Model 50 had a 16550 built in.

>The first 4 months or so of 55sx's have original 16550 not 16550A[NF]
>implementations.  The 16550 contained a defective buffer and would not
>switch into FIFO mode.

>HAven't been able to try because 1.167f will not work with my SCSI drive.

It seems to work on my 55sx.  I get a status of "buffer=on" from the mode
display, but I have no real way to confirm it, as that machine has only
a 2400 baud modem.

Anyone know a way to check for sure?

Jason
--
Jason Campbell  |  Stanford University  |  "Loose _wait_ now, ask me how!"

:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) just in case I forgot a few.

 
 
 

1. 16550, ps/2 m55sx and


GH>First I guess I should ask if anyone knows for sure that the PS/2 Model 55sx
GH>has a 16550 UART in it's serial port. My understanding was that all PS/2's
GH>including and above the Model 50 had a 16550 built in. If this is true why
GH>doesn't OS/2 recognize it? I do:
GH>   MODE COM1:BUFFER=ON
GH>       or
GH>   MODE COM1:ENHANCED=ON
GH>and OS/2 tells me that both BUFFER= and ENHANCED= are invalid for my serial
GH>device! I think I remember reading that the first 16550's had some
GH>problems, is there a way to distinguish the bad 16550's from the good ones?
GH>Has anyone else gotten their m55sx to use the 16550? If it is indeed a bad
GH>16550 will IBM replace it? I've had the machine for about 1.5 years so the
GH>warranty is no longer there.

Do you have the line:

DEVICE=C:\OS2\COM02.SYS

in your config.sys? This is required to enable the 16550. Watch the
initial messages that are displayed when the device drivers are
being loaded. It should say something like 'Enhanced Hardware
Buffering Enabled"

    STEPHEN
    ^^^^^^^    :-)


 Entered 02-09-92 at 9:19pm in Downsview, Ontario

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