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Re: Which newsgroup to discuss details of serial-port programming?

Cross-posted to 3 groups.

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I know that there have been many varients of the 8250 uart over the
years, and making this even more fuzzy is knowing the exact performance
specs when the uart is incorporated into a motherboard chipset or
multifunction asic, but...

The issue I'm dealing with is writing a set of data (16 bytes) to a uart
using I/O commands (I'm reading and writing directly to the ports, not
using any bios routines, not using any interupts, etc).

If the more modern versions of these uarts have 16-byte read/write
buffers, then I should be able to fire off a set of data (16 bytes)
without having to monitor the fifo and tx buffer status bits (bits 5 and
6 of uart register 5).  But when I try that, the computer on the
receiving end doesn't like what it's getting (the receiving program
hangs or crashes).

But when I monitor the status of those bits as I'm writing the data, and
only write new data when one (or the other) of those bits are not low,
then the data exchange works fine.

It's almost like the uart is acting like it has only a 1-byte write fifo
- but I am enabling the fifo's by writing the appropriate data to other
registers.

I'm using 2-port PCI card for this work, with the uart integrated into a
single ASIC that is also handling the PCI bus interface.  This work is
being done in a pure DOS environment (not running under linux or NT) so
there is no OS interference or virtualization happening here.

Ideas?

Comments?

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Thread

Which newsgroup to discuss details of serial-port programming? DOS Guy <DOS@Guy.com> - 2012-02-07 19:41 -0500
  Re: Which newsgroup to discuss details of serial-port programming? pete@nospam.demon.co.uk - 2012-02-08 07:13 +0000
  Re: Which newsgroup to discuss details of serial-port programming? "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-08 03:12 -0500
  Re: Which newsgroup to discuss details of serial-port programming? DOS Guy <DOS@Guy.com> - 2012-02-08 08:37 -0500
    Re: Which newsgroup to discuss details of serial-port programming? DOS Guy <DOS@Guy.com> - 2012-02-08 09:29 -0500
      Re: Which newsgroup to discuss details of serial-port programming? Jim Leonard <mobygamer@gmail.com> - 2012-02-08 07:20 -0800
        Re: Which newsgroup to discuss details of serial-port programming? DOS Guy <DOS@Guy.com> - 2012-02-08 21:38 -0500
          Re: Which newsgroup to discuss details of serial-port programming? "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-09 02:16 -0500
    Re: Which newsgroup to discuss details of serial-port programming? pete@nospam.demon.co.uk - 2012-02-08 18:55 +0000
      Re: Which newsgroup to discuss details of serial-port programming? DOS Guy <DOS@Guy.com> - 2012-02-08 22:12 -0500
        Re: Which newsgroup to discuss details of serial-port programming? Jim Leonard <mobygamer@gmail.com> - 2012-02-09 07:23 -0800
          Re: Which newsgroup to discuss details of serial-port programming? DOS Guy <DOS@Guy.com> - 2012-02-09 19:57 -0500
            Re: Which newsgroup to discuss details of serial-port programming? Jim Leonard <mobygamer@gmail.com> - 2012-02-10 07:13 -0800

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