Member Since: April 4, 2010

Country: United States


Spoken Languages


Programming Languages

Mostly C. Bits of Lisp/Scheme. Little C++. Various assembly languages as needed. Microsoft XL (great modeling tool). PERL for PERL-appropriate things. HTML. Whatever is needed.


IEEE, ARRL, various ham radio clubs, Barbershop Harmony Society, Sounds of Concord, …


MIT mostly.


I do computer things. Software, firmware, electronics, analog, RF as needed, mechanical design as needed, integrating disparate systems.


Interesting people. Doing projects that teach me new things. Singing and listening to harmony. Helping people to do better tomorrow than they did today. Trying to do so myself.


  • I’ve also added new-line processing, so it is a closer implementation of a glass-TTY. I found that writing strings to the screen was annoying without the backpack handling line endings.
    The algorithm should do something “reasonable” for PC and Linux/Unix line endings. I don’t know the MAC convention.
    Email me at carl dot mikkelsen at gmail dot com for a source distribution.

  • The code is too large to post in forums – I tried.
    Does SparkFun have an FTP site? Or is there a CVS/SVN server? I have code to contribute, but no means to contribute it.
    Does this go back through Google Code?
    Do I need to create a SourceForge project for it?
    Should I put it on my own web site?
    All of these seem a little haphazard. Surely there must be a way to get code back to SparkFun (where I got the original code)?
    What are the procedures and rules for working with SparkFun to improve your products?
    – Carl

  • I fixed the last bug that currently annoys me, and have a new main.c to distribute. For my purposes, it not only works better, but it turns out that I no longer ever get an X-OFF character. Still, it’s good to have it built in so noone, including me, needs to worry about overrunning the Serial Graphic LCD Backpack input buffer.
    I can’t simply include the file here, as it is too big. How does one release code into the Arduino/AVR development society?
    The display is ever-so-much more responsive now, and I’m getting no extraneous pixels or screen clearing events. It’s been rock solid for hours.
    I don’t have a good test suite, so although i’ve tried to limit the scope of my changes to those things which I am testing, I welcome more testing or code review by anyone interested.
    – Carl

  • I have rewritten some of the serial communication code for the Graphic LCD Backpack to:
    1) implement a true, IRQ safe, circular buffer
    2) observe proper buffer discipline
    3) remove the “command near the end of buffer” cases
    4) increase the buffer to 512 bytes
    5) send X-OFF (S> when the buffer is ¾ full
    6) send X-ON (Q> when the buffer is back to ½ full
    This now has resolved some of the bugs I saw, and I can drive it much faster since the Arduino driving it need not guess how fast it can send.
    There are still a few random pixels appearing on the bottom line – probably a problem in the line-drawing code, as that is what I am heavily using.
    My question is, how do I release this code back to SparkFun (or anyone else?).
    Anyone wanting the code can email me at carlmikkelsengmailcom.
    I have a dual-Arduino test bench right now :) A Duemilanove as the ISP, and a MEGA as the test engine. Once I wired it up properly, it works quite well. Cudos to the Arduino development team.
    – Carl

No public wish lists :(