Good morning everyone,
I’m noticing a behavior on my device, analyzing the journal: is this correct behavior?
At the hardware level I have a LAN9514 (USB hub and Ethernet) no devices connected to USB, the usart connection is enabled and at the hardware level it is connected to a peripheral. The state of this connection is not idle only during the first seconds of startup of the microprocessor.
Can you help me?
Thank you 
Perhaps, it’d help, if you gave a little more details, like;
/dev/ttyS0?LAN9514 about? (Microchip USB Ethernet?)If you’re using the BPi-M2 Zero, you wouldn’t need a USB-Ethernet adaptor - the Allwinner H2+/H3 has an Ethernet PHY - see, also “Transformerless Ethernet, with TI PDF paper” BPI-M2 Zero Packet loss - #6 by platymew
Hi @platymew,
1- I do not use /dev/ttys0. I only use /dev/ttyS3 for serial communication with a microcontroller.
2- The LAN9514 is a simple USB converter (1xEthernet + 4xUsb Hub), I use two network interfaces, the Eth0 (from BPI board PIN define see: Development_section) is used to transfer the network connection from Bananapi to another device, it is a simple bridge configuration to a microcontroller. The eth1, from which I receive the internet connection, is obtained thanks to the LAN9514 chip, and works fine, but I don’t know how to understand if it is the one contributing to the journal messages.
3- M2 Zero
As explained above I need two ethernet connections, one to receive internet and the other for ethernet bridge connection to another device that must be connected to the network. More in detail, I take the connection either from eth1 or from wlan0 and make them available through eth0 to a microcontroller.
I hope I have explained the configuration better. The hardware design is working well, and has been thoroughly thought out.
The original question concerns the reasons for those specific messages relating to the reported connection: /dev/ttyS0 which I don’t seem to be using. How can I understand better?
A thousand thanks