as the title suggested, I am trying to add 2 ethernet interface and several USB port to my Rasp Pi. Since this will be used in project and the client wanted me to make the device as small as possible, using already available USB hub and USB to ethernet is not possible. In fact, I did so for first prototype, and it is rejected.
So, because RPi used Lan9512 as the ethernet controller and USB hub, I think I could cascade the chip to give me the additional two ethernet port and USB port for USB to serial chip, USB to parallel chip, and a 3G modem. The configuration is as follow:
- RPi ==> LAN9512 #1 ==> LAN9512 #2, 3G Modem + Ethernet Port #1
- LAN9512 #2 ==> USB-Serial Chip, USB-Parallel chip + Ethernet Port #2
Please see image below for more clear description:
Unfortunately, my design is not working. I have not attached the USB-Serial, USB-Parallel, and 3G Modem yet, still not working. Running ifconfig only shows the original eth0 port, and lsusb also only shows the default USB hub. My additional Lan9512 is not detected at all.
My question is, is my design concept flawed (e.g. I cannot just cascade a USB hub on top on other hub, and then cascade it again)? Or do I need to recompile the OS, make some driver adjustment perhaps? Because I thought because Lan 9512 is basically a USB device, I can just plug it into RPi USB port, and use it as hub for other Lan9512.
I checked the RPi USB port, connect it directly to the USB Serial and USB Parallel circuit that I made, and it works (running lsusb shows FTDI devices that I used). I checked the voltage across the LAN9512 chip, and it shows 3.3v which is the correct operating voltage of LAN9512.
I am pretty confused, so if anybody can give me heads up, that will be great. Thanks guys!