2.2.12: serial driver swapping characters?

Ulrich Windl (ulrich.windl@rz.uni-regensburg.de)
Wed, 8 Sep 1999 10:16:57 +0200


Hello,

my 386SX 16 MHz is receiving time strings at 9600 baud. I see wrong
time strings quite frequently. Inspecting the data, it looks like two
characters are swapped or duplicated or swallowed occasionally. For
my machine this may mean "high load". I'll show some strings to give
you an impression of what I mean:

"\x0201.09.99; 3; 01:41:117 S \x03"
"\x0201.09.99; 3; 01:43:17; \x03"
"\x0201.099.9; 3; 01:46:54; S \x03"
"\x0201.09.99; 3; 01:48:37 ; S \x03"
"\x0201.09.99; 3; 01:49:4; S \x03"
"\x0201.09.99;; 0 01:53:02; S \x03"
"\x0201.099.9; 3; 01:56:21; S \x03"
"\x0201.09.99; 3; 01:59:0;4 S \x03"
"\x0201.099.9; 3; 02:05:44; S \x03"
"\x0201.09.99; 3; 02:08:3;0 S \x03"
"\x0201.099.9; 3; 02:15:10; S \x03"
"\x0201.09.99; 3; 02:17:42; S \x03"
"\x02010.9.99; 3; 02:18:22; S \x03"
"\x0201.099.9; 3; 02:24:34; S \x03"
"\x0201.09.99; ;3 02:28:41; S \x03"
"\x0201.099.9; 3; 02:33:58; S \x03"
"\x0201.099.9; 3; 02:34:03; S \x03"
"\x0201.09.99; 3; 02:36:32; S \x03"
"\x0201.09.99; 3; 02:3:959; S \x03"
"\x0201.099.9; 3; 02:43:27; S \x03"
"\x0201.09.99; 3 ;02:46:22; S \x03"
...
"\x0208.099.9; 3; 09:58:16; S \x03"
"\x0208.099.9; 3; 09:58:18; S \x03"
"\x0208.09.99; 3; 10:01:85; S \x03"
"\x0208.09.99; 3; 10:02:4:7 S \x03"
"\x0208.09.99; 3; 10:0:403; S \x03"
"\x0208.09.99; 3; 100:6:09; S \x03"
"\x0208.099.9; 3; 10:07:23; S \x03"
"\x0208.09.99; 3; 10:11:90; S \x03"

A correct time string looks like this:

"\x0208.09.99; 3; 10:13:42; S \x03"

Is the CPU really too slow for 9600 Baud? If so, shouldn't characters
simply be missing in the input?

Regards,
Ulrich Windl

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