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<p>Yes, the HDLC encoding of the AX5043 appears to be the framing
and modulation required by AX.25. My next task is to create a
sample application for the Digital Transceiver for the Raspberry
Pi (that's what I call the Raspberry Pi dev board with the AX5043)
that transmits APRS. It will be based on work done by Libre Space
Foundation that has reportedly developed APRS for AX5043 using a
STM32 processor (see
<a class="moz-txt-link-freetext" href="https://gitlab.com/librespacefoundation/pqws">https://gitlab.com/librespacefoundation/pqws</a>).</p>
<p>The reference code for the sample software developed for the
Digital Transceiver for the Raspberry Pi is located at
<a class="moz-txt-link-freetext" href="https://github.com/BrandenburgTech/DigitalTxRxRPi">https://github.com/BrandenburgTech/DigitalTxRxRPi</a>. I'll be
publishing the hardware files as soon as that task hits the top of
my task list (so many fun and necessary tasks but so little time
in a day). In the meantime, I can provide assembled boards as I
get parts and assemble them.</p>
<p>Of course, when I get the hardware files published, you can build
your own (and improve the board).</p>
jb<br>
<br>
<div class="moz-cite-prefix">On 6/5/2018 11:48 AM, Zach Leffke via
Ground-Station wrote:<br>
</div>
<blockquote type="cite"
cite="mid:8366d2fa-a9ae-72d0-4beb-f825f8f49cc1@vt.edu">
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<p>This is awesome! to fixate on one detail, that is not related
to the IHU..........I'm very interested in the AX5043
(particularly the native HDLC features, which sound suspiciously
close to AX.25 with a little help from the Pi/MCU). Will the
Raspberry Pi dev board / reference code also be on github at the
link provided? any ETA for that? Does that already exist
somewhere on github?</p>
<p><br>
</p>
<p>Thanks!</p>
<p>-Zach, KJ4QLP<br>
</p>
<pre class="moz-signature" cols="72">Research Associate
Aerospace Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305</pre>
<div class="moz-cite-prefix">On 6/5/2018 11:54 AM, Michelle
Thompson via Ground-Station wrote:<br>
</div>
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<div>A conference call was held on 31 May
2018. Presenting was Jonathan Brandenburg,
concerning his IHU project that he wishes
to publish. </div>
<div><br>
</div>
<div>Open Research Institute will support
publishing this open source Integrated
Housekeeping Unit (IHU) design intended
for amateur radio satellite service
payloads. An IHU is a flight computer,
controlling all the elements of the
payload.</div>
<div><br>
</div>
<div>The call was held courtesy of National
Instruments conference bridge. Thank you
to Neel Pandeya for making it possible and
for supporting open source hardware and
software designs. </div>
<div><br>
</div>
<div>The design team for this IHU consists
of Zach Metzinger, Jordan Trewitt, Bill
Reed, and Jonathan Brandenburg. This
started in earnest about a year ago. It it
not radiation hardened by design, but is
entirely appropriate for low earth orbit
(LEO) use. </div>
<div><br>
</div>
<div>Initial design work was presented at
the 2017 AMSAT Symposium. </div>
<div>This is a failover IHU design. It was
two fault-tolerant processors. The
processor is TI Hercules and the part
number is TMS570LS0914PGE. Each processor
has two cores, and each core operates in
lock-step. There is some flight heritage
with this part from the ICI Radar
Satellite and a NASA Robotic ARM. </div>
<div><br>
</div>
<div>Included in the design are twin
transceivers. The transceiver selected is
the AX5043.</div>
<div><br>
</div>
<div>A power amplifier design is in
progress. </div>
<div>There is error correction on the
memories. </div>
<div>This IHU has two “sides”, with one
Hercules and one transceiver on each side.
There is diversity in the voltage
regulators, with the primary side powered
by a MAX1556A regulators and a secondary
side powered with LTI963As. The diversity
in voltage regulators is intended to
provide additional resilience. For each
side, there is a 3.3volt rail and a
1.2volt rail.</div>
<div><br>
</div>
<div>Software development has only just
begun. Layout is approximately 80%
complete. </div>
<div><br>
</div>
<div>The board has 4 layers and relatively
good power consumption based on prototype
measurement. </div>
<div><br>
</div>
<div>UPSat from Libre Space was also
introduced and referenced.</div>
<div><br>
</div>
<div>OreSat is interested in collaborating
and learning more about this design.</div>
<div><br>
</div>
<div>Our consensus is CANbus or Ethernet for
flight hardware.</div>
<div><br>
</div>
<div>Jonathan has also made a Raspberry Pi
daughterboard for the AX5043. This allows
development with the transceiver
independent of the Hercules or IHU. </div>
<div><br>
</div>
<div>The drawbacks to the Hercules include
terrible documentation and a cumbersome
parameterized code generation process for
development. Jonathan believes he is
getting a handle on this and there is the
possibility of him producing improved
documentation for this design. </div>
<div><br>
</div>
<div>We also discussed the VA10820 -
Radiation Hardened ARM® Cortex®-M0 MCU <a
href="https://www.voragotech.com/products/va10820"
moz-do-not-send="true">https://www.voragotech.com/products/va10820</a>.
This is approximately $700, but has good
stats and a well-documented toolchain.
There is at least one design that is open
source that could be used as a basis for
an IHU. </div>
<div><br>
</div>
<div>Jonathan to publish the IHU at <a
href="https://github.com/phase4space/payload-IHU"
moz-do-not-send="true">https://github.com/phase4space/payload-IHU</a></div>
<div>Jonathan and Michelle to press for
review of the design.</div>
<div><br>
</div>
<div>Michelle to publish minutes.</div>
<div><br>
</div>
<div>Michelle to arrange for additional IHU
conference calls. </div>
<div><br>
</div>
<div>Microsemi’s SmartFusion2 and PolarFire
devices were brought up outside of the
meeting. They are actively advertising
radiation hardening for these parts and
they may be available now and should be
discussed. </div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
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<pre class="moz-signature" cols="72">--
Jonathan Brandenburg
1-214-213-1066
<a class="moz-txt-link-abbreviated" href="mailto:jonathan@jonathanbrandenburg.com">jonathan@jonathanbrandenburg.com</a>
-----------------------
When possible, please sign and encrypt your communication. See <a class="moz-txt-link-freetext" href="https://ssd.eff.org">https://ssd.eff.org</a>
I updated my PGP certificate on December 8, 2015. Please update your keychain:
PGP certificate fingerprint: 824E 8871 5474 61F7 09D4 9B67 8AFC 1E70 924D B20</pre>
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