<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0"><channel><title><![CDATA[M5Stack CoreS3 SE + COMMU display problem when replugging USB]]></title><description><![CDATA[<p dir="auto">hi</p>
<p dir="auto">i have a weird problem with the CoreS3 SE + COMMU. i have some RS485 device and data coming on a UART configured to the CoreS3 port (next to the USB-C connector). data is displayed/updated on the screen. during (arduino) development all worked fine. flashing code over USB automatically restarts the code and i have a nice display updating every second.</p>
<p dir="auto">but i found out that not flashing the CoreS3 and just connecting USB-C for power (and logging) i get a somewhat scrambled display.</p>
<p dir="auto">i have chatted quite a bit with the M5Stack AI chat but it is still not fixed. everytime i just connect USB-C it is a bit scrambled. re-flashing the same code give a nice and clean display. what is going on??</p>
<p dir="auto">my initialization code is (most of it suggested by M5Stack AI):</p>
<pre><code>    auto cfg = M5.config();
    cfg.internal_imu = false;
    cfg.internal_mic = false;
    cfg.clear_display = true; // Ensure display is cleared during init

    // Initialize M5 with proper power sequencing
    M5.begin(cfg);

    // Explicitly reset the AW9523 IO expander that controls display power
    Wire.begin(11, 12); // CoreS3 internal I2C bus pins
    Wire.beginTransmission(0x58); // AW9523 address
    Wire.write(0x00); // Reset register
    Wire.write(0x00); // Perform hardware reset
    Wire.endTransmission();
    delay(100);

    // Re-initialize display with full reset
    M5.Display.init();
    M5.Display.setBrightness(128);
    M5.Display.fillScreen(TFT_BLACK);
    M5.Display.display();
</code></pre>
<p dir="auto">the wire command actually give errors so i do not think it is doing anything:</p>
<pre><code>E (3570) i2c.master: I2C transaction unexpected nack detected
E (3571) i2c.master: s_i2c_synchronous_transaction(945): I2C transaction failed
E (3572) i2c.master: i2c_master_multi_buffer_transmit(1207): I2C transaction failed
</code></pre>
<p dir="auto">here is a "scrambled" picture:<br />
<img src="/assets/uploads/files/1767890723211-replug-usb-small.jpg" alt="replug-usb-small.jpg" class=" img-fluid img-markdown" /></p>
<p dir="auto">and this after reflash:<br />
<img src="/assets/uploads/files/1767890738924-reflash-small.jpg" alt="reflash-small.jpg" class=" img-fluid img-markdown" /></p>
<p dir="auto">help?!</p>
]]></description><link>https://community.m5stack.com/topic/8001/m5stack-cores3-se-commu-display-problem-when-replugging-usb</link><generator>RSS for Node</generator><lastBuildDate>Sat, 07 Mar 2026 15:23:42 GMT</lastBuildDate><atom:link href="https://community.m5stack.com/topic/8001.rss" rel="self" type="application/rss+xml"/><pubDate>Thu, 08 Jan 2026 16:49:38 GMT</pubDate><ttl>60</ttl><item><title><![CDATA[Reply to M5Stack CoreS3 SE + COMMU display problem when replugging USB on Wed, 14 Jan 2026 15:38:06 GMT]]></title><description><![CDATA[<p dir="auto">it was caused by the CS of the LAN Module13.2. switching the jumper to the alternate position fixed the problem...</p>
<p dir="auto">so far these seem to work (CoreS3 SE+COMMU+Lan Module13.2+DIN Base):</p>
<pre><code>int  cs_pin  = 13; // jumper right
int rst_pin = 0; // jumper left 
int  int_pin = 10;// jumper left
</code></pre>
]]></description><link>https://community.m5stack.com/post/30457</link><guid isPermaLink="true">https://community.m5stack.com/post/30457</guid><dc:creator><![CDATA[frank_b]]></dc:creator><pubDate>Wed, 14 Jan 2026 15:38:06 GMT</pubDate></item><item><title><![CDATA[Reply to M5Stack CoreS3 SE + COMMU display problem when replugging USB on Fri, 09 Jan 2026 09:20:16 GMT]]></title><description><![CDATA[<p dir="auto"><a class="mention plugin-mentions-user plugin-mentions-a" href="https://community.m5stack.com/uid/4037">@felmue</a> thanks for your message: i also had the "din base" and the "lan module" connected (but not used). disconnecting the lan module fixes the problem!!</p>
]]></description><link>https://community.m5stack.com/post/30425</link><guid isPermaLink="true">https://community.m5stack.com/post/30425</guid><dc:creator><![CDATA[frank_b]]></dc:creator><pubDate>Fri, 09 Jan 2026 09:20:16 GMT</pubDate></item><item><title><![CDATA[Reply to M5Stack CoreS3 SE + COMMU display problem when replugging USB on Fri, 09 Jan 2026 01:43:00 GMT]]></title><description><![CDATA[<p dir="auto">Hello <a class="mention plugin-mentions-user plugin-mentions-a" href="https://community.m5stack.com/uid/149902">@frank_b</a></p>
<p dir="auto">have you tired without COMMU module stacked?</p>
<p dir="auto">Thanks<br />
Felix</p>
]]></description><link>https://community.m5stack.com/post/30422</link><guid isPermaLink="true">https://community.m5stack.com/post/30422</guid><dc:creator><![CDATA[felmue]]></dc:creator><pubDate>Fri, 09 Jan 2026 01:43:00 GMT</pubDate></item></channel></rss>