Closing Ethernet

Leon Pollak leonp at
Tue Oct 21 20:57:03 UTC 2008

On Tuesday October 21 2008, Gene Smith wrote:
> This sounds similar to what I just solved, but maybe in the opposite
> direction. Bootloader (uMon) running ethernet/UDP loads RTEMS and
> branches to RTEMS at startup. Eth driver in bootloader was still doing
> DMA to RAM and caused RTEMS to re-init ethernet and crash while it was
> starting up. Had to reset ethernet hardware on entering RTEMS (start.S)
> (or could do same thing before leaving bootloader). So adding code to
> reset the mac and phy at beginning of start.S stopped ethernet activity
> and fixed it. There may be better way but this worked for me but is
> definitely not a "graceful" shutdown.
Gene, thank you a lot!
I shall consider this issue too, as I also run uMon.

Hmmm... AFAIK, as uMon does only polling, there should be no problems with 
Ethernet still "active", no? Well, only if you use the uMon RAM for the 
What I do is: I leave 0-64KB RAM for uMon purposes and load the application to 
the 0x10000 address. Thus DMA may continue to write its data.

But I have the problem returning to uMon from the application - the RTEMS 
driver does use interrupts.

As for just now, I simply zero some FEC registers before exiting in the 
application, but this is not good, as this work must be done by the driver.


More information about the users mailing list