I never did figure this bug out.  I ended up swapping the DS275 for a MAX233
and all is well, if that makes any sense.

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Dan Michaels
Sent: Monday, May 21, 2001 9:11 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]: serial garbage


At 06:52 PM 5/21/01 -0600, you wrote:
>For
>
>ABCDEFGHIJKLMNOPQRSTUVWXYZ
>
>I get
>
>oaua?c?iuiyiyiyo?uy?yuyy
>

Did you try the simple h.w. loopback test described earlier?

The VERY FIRST thing to do is to determine whether the problem
is in h.w. or s.w. - else you can be spinning your wheels for
days.












>(U and W didn't produce anything
>
>Raw log shows the following hex output:
>
>F8 E3 FC E6 FE E7 FE EC FB EF FF EE FF EF FF F8 FE FB FF FE FF FC FF FF
>
>
>-----Original Message-----
>From: pic microcontroller discussion list
>[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Barry Gershenfeld
>Sent: Monday, May 21, 2001 1:48 PM
>To: PICLIST@MITVMA.MIT.EDU
>Subject: Re: [PIC]: serial garbage
>
>
>incorrect characters.  I put a
>>simple "echo" program in the PIC to check.  I press an "A", I should get
an
>>"A" back, but instead I get some other character, but always the same
>>incorrect chacter for a given key.  I checked the math to see if it was a
>>simple pattern (bit 8 or something), but no pattern.  Some keys produce
the
>>same hex value.
>
>Are any of the characters correct?   Mismatched parity will give
>about 50% of the characters wrong, and not in any expected order
>(like, not every other one).
>
>Single bit errors sometimes aren't obvious at first glance,
>either.  If you type ABCDEFGHIJKLMNOPQRSTUVWXYZ, what do
>you get back?
>
>Barry
>
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