https://blog.lazy-evaluation.net/deContents © 2025 <a href="mailto:dzu@member.fsf.org">Detlev Zundel</a> Wed, 10 Dec 2025 16:11:11 GMTNikola (getnikola.com)http://blogs.law.harvard.edu/tech/rsshttps://blog.lazy-evaluation.net/de/posts/embedded/zephyr-st-simcom-demo.html?pk_campaign=feedDetlev Zundel<div><p> Trying to understand the new <a href="https://docs.zephyrproject.org/latest/connectivity/networking/api/gsm_modem.html">cellular modem</a> subsystem in Zephyr, I realized that building a working demo system should be the best way forward. Having an evaluation board of the <a href="https://en.simcom.com/product/A7683E.html">A7683E</a> available, the first step was to pick a well suited eval board to match the module. </p> <p> As it turns out, the Simcom module runs at 1.8V and even on the evaluation board there are no level shifters. So that quickly gave me the first hard requirement, namely that the UART needs to be run at 1.8V. </p> <p> Looking at my collection of recent MPU eval kits, I realized that the <a href="https://www.st.com/en/evaluation-tools/nucleo-u575zi-q.html#documentation">NUCLEO-U575ZI-Q</a> could run completely on 1.8V by a simple jumper setting. On the other boards it would have been more involved to define the UART pins to run on 1.8V, so I decided to use this eval board for the MPU part. </p> <p> So the aim of this blog post is to document how I implemented the demo on this hardware combination: </p> <div style="text-align:center" class="imageblock" id="org60743e2"> <div id="orga69b225" class="figure"> <p><img src="https://blog.lazy-evaluation.net/de/images/zephyr-st-modem.jpg" alt="zephyr-st-modem.jpg" title="Lab Prototype" align="middle" width="150"> </p> </div> </div> <p><a href="https://blog.lazy-evaluation.net/de/posts/embedded/zephyr-st-simcom-demo.html?pk_campaign=feed">Weiterlesen…</a> (35 min verbleiben zum Lesen)</p></div>https://blog.lazy-evaluation.net/de/posts/embedded/zephyr-st-simcom-demo.htmlSun, 06 Apr 2025 12:05:41 GMT