Steven: The primary reason for parts on both sides of the boards is just space constraint. With an extra half square inch of space, everything could be on one side. I do like to keep the transient suppressor as close to the RJ-45 connector as possible. You would still need a four layer board to do the power distribution cleanly.
In this design, the MAC address can not be assigned by the Linux driver. It takes a Windows app, from the Microchip website, that needs to access the LAN9500A chip from both sides to program it. That is, it needs to access both the USB-2 connection to the LAN9500A, and have the Ethernet connection from the LAN9500A on the same sub-net as the PC running the programming app. Even though the MAC address is held in an EEPROM, I don't think there would be any way for the user to change it without reproducing the programming connections. I am not aware that Microchip sells preprogrammed EEPROMS with the MAC addresses, normally you get blank EEPROMS and you supply and program the MAC address. Although for extra money, you can get either Microchip or some of the distributors to program memory parts. I have heard that Microchip will sell a small number of MAC addresses as a courtesy, but I have not done that. The normal process is to buy a block of MAC assignments from the IEEE which is the global coordinator. If you buy a large enough block, you get your own OUI. --- Graham == On Mon, Aug 5, 2019 at 3:21 PM Steven Keller <skeller.k6...@gmail.com> wrote: > Graham, > If you don't mind could you answer a few questions? > You have parts on both sides of the board. Is this primarily because of > the size constraint or to keep traces short as possible? > Is it possible for the driver software to load the MAC address of the > Beagle Bone into the LAN9500A? It does not appear that the preprogrammed > MAC address EEPROMs from Microchip work with these USB-to-Ethernet chips. > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAC_N71qynDOqbJaee0j9oW1KcUE0P%3Ds5%3DxY_VB5%2Bg0T6xk-rrg%40mail.gmail.com.
