Hi Pavel,
This information is quite helpful. Thank you!
Isaac
On 06/06/2016 04:36 AM, Pavel Pisa wrote:
Hello Isaac,
On Thursday 02 of June 2016 17:09:31 Isaac Gutekunst wrote:
On 06/01/2016 07:18 PM, Pavel Pisa wrote:
Hello Isaac,
On Wednesday 01 of June 2016 23:09:39 Isaac Gutekunst wrote:
I believe I solved all my problems. Not enough memory. After updating
the linker script to use SDRAM, everything appears to be working well!
(Knock on wood).
I think that SAM V71 setup with 2 MB of external SDRAM is not much
above minimal limit for use of RTEMS with BSD networking.
If the single chip solution with only 128kB of internal SRAM
is considered (may be with additional 128kB which can be borrow
for some buffer from the instruction TCM) then it cannot
be used with libBSD based networking. So it would worth
to consider lwIP. I hope that it would be integrated to
the RTEMS file operations API as part of this year GSoC.
So this option worth to be considered to support
networking on the small systems.
Hi Pavel,
Thanks for the info.
We will definitely be adding the largest SDRAM chip we can find to our
final board, so I imagine we will be okay.
Based on the weirdness I've experienced, not having enough RAM doesn't
necessarily result in a nice error message. What do you think is a good
amount of RAM to give the stack, and how can I be sure it's enough?
I have no experience with libBSD on RTEMS. But I would expect that
mentioned 2 MB are minimum for stack of this level/complexity.
When I compare that with Linux then 8 MB SDRAM has been successfully
used in many wireles routers etc. It has been minimum and I consider
that it is not enough for latest kernel versions and full GLibC.
Then 32 MB is OK for Linux.
I expect that 8 MB should be OK for RTEMS and libBSD but some
statistic about amount of allocated memory for example for
4 and 10 TCP/IP connections from Chris or Sebastian would
be interresting. From my experience with LPC, we have
found that 512 kB of Flash is too small for complete
system code+initialization data if we want full RTEMS
support for networking (TCP, TFTP, remote shell)
even if we have 32 MB of external SDRAM.
1 MB of Flash should be enough for reasonable size application.
2 MB even for larger application.
As for classical RTEMS stack, it has lower memory demand
then libBSD, so I expect that 2 MB would be probably OK.
As for lwIP, we have some experience with TMS570.
1 or 2 MB of Flash is OK. 256 kB of internal SRAM
is OK for something like 4 to 10 TCP/IP connections.
Best wishes,
Pavel
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