Hello, On Mon, Apr 20, 2020 at 11:01:46AM +0200, Szabolcs Hubai wrote: > I have a CP2102 USB to TTL module, and used with "minicom -D /dev/ttyUSB0". > > > Intereestingly, when I connected with serial to the router it was > sometime unstable: > * refuse to start > * freeze at boot soon after: "Error applying setting, reverse things > back" messge
I can't tell if it's exactly the problem there but when working with UARTs it's good to keep in mind that Tx idles high and so when you disconnect power from your target you'll have your UART module feeding some current to the SoC's Rx from the module's Tx and that often confuses the hardware. Proper way to fix this would be to feed USB UART module's output buffers from target's Vcc (that's why most UART headers have that pin); the next best option would be to not have target's Rx connected at all (and hotplugging it just before you actually need it); yet another possible way might be to add a 1k (or more) resistor in series to limit this current. -- Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software! mailto:fercer...@gmail.com _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/mailman/listinfo/openwrt-devel
