Low Memory with OpenWRT

Started by t35tB0t, August 24, 2015, 05:28:07 am

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Shown on you-tube, RT5350F booting OpenWRT - showing only 5MB (17%) free.   >:(   Want to be able to use python+openwrt and other packages.  Memory is cheap, time is not.  How can we increase both flash and ram on the RT5350F... e.g. to at least 16MB/64MB. Looking up parts, it looks like might be able to swap out flash to 16MB or jump thru hoops to run OpenWRT from USB port.  Might be able to double-stack SDRAM chips (with CS1 wire cross over).  But what a pain.  why cripple a board like this!? :-\


Config the software with fewer options?

Or... imagine Olimex do what you want.  Say, in 6-12 months.
If you want it sooner, offer them money and commit to quantity purchase.

Or... change boards entirely.  Lots have more RAM etc.



What's wrong with using a tiny USB flash drive to extend space? The tutorial at [1] describes it at detail - once you have your drive formatted to ext4, it's two commands and changing a few words in a config file; I would hardly call that "jumping through hoops" - you even get the single package you need (block-mount) pre-installed in the latest Olimex image. Granted, that doesn't much help you with RAM if you run out, unless you use some of the USB drive as swap - it might help if most of what eats your memory is idle most of the time, but not so much if everything is actively used all the time. You should have chosen a bigger board for that though...

[1] - http://wiki.openwrt.org/doc/howto/extroot (scroll way down to "Chaos Calmer")


Thanks blinkenlight.  That's very helpful.  Should work for a manual edit on one unit.  Next up is figuring how to make this work with remote sysupgrade and pre-built into the bin file via OpenWRT BuildRoot.  Imagine 50 devices on mesh network and no easy physical access.  Looking at the SoM, it should be trivial to double-stack the SDRAM and have 64MB.  Swapping the flash is also easy but may be limited to 16MB - or now I can try to use USB expansion approach.  The reason for sticking with these SoMs is that they run the flash-friendly and honed-for-embedded-use OpenWRT out of the box.  The imx233 also has OpenWRT support but not as well integrated ethernet.  And most of the other boards/MCUs are really targeting "multi-media" boxes.  The Olimex RT5350 with I/O-friendly EVB is somewhat of a rare gem for simple embedded smart control.


Progress update - I stacked another 32MB on top of the existing 32MB SDRAM using an Alliance AS4C16M16S-6TAN (the WinBond equivalent was not available). It is not working.  Poking around with u-boot, didn't help.  Looking at the RT5350's SYSCFG registers shows that it is in 16/32,32*2 size mode via bootstrap.  However, looking at the Ralink "manual", we need to see a three bit code from the bootstrapping in order to acknowledge 64mb.  Has anyone got 64MB running with the RT5350?