assemble on 2 sides is no issue
populate one side, reflow solder, populate the other side, reflow solder
the surface tension will keep the parts on the other side IF the solder
even melts
On 8/5/2019 5:57 PM, Steven Keller wrote:
Graham,
Thanks so much! That should be enough to get me started. I wanted to
avoid parts on the bottom of the board as it makes assembly more
difficult. Board size isn't too much of a problem. The extra EEPROM
programming step is a bit of pain but not impossible.
Thanks again!
On Monday, August 5, 2019 at 6:30:13 PM UTC-5, Graham wrote:
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 <skelle...@gmail.com
<javascript:>> 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
<mailto:beagleboard+unsubscr...@googlegroups.com>.
To view this discussion on the web visit
https://groups.google.com/d/msgid/beagleboard/86df597a-f542-4f96-b82e-35982fa3db38%40googlegroups.com
<https://groups.google.com/d/msgid/beagleboard/86df597a-f542-4f96-b82e-35982fa3db38%40googlegroups.com?utm_medium=email&utm_source=footer>.
--
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/72d488f5-2ac8-4b27-d111-ec66ad22dab6%40gmail.com.
