• Registered: 2010-08-13
  • Posts: 89

Topic: Adding more ram

I know that our devices are limited in ram space for a desktop OS, but cant we add ram by using virtual space on the the sd card or even a usb flash drive?

2 Reply by ryoohki (edited by ryoohki 2011-06-26 23:07:58)

  • From: San Francisco Bay Area, CA, US
  • Registered: 2008-12-02
  • Posts: 19

Re: Adding more ram

You can add a swap device or swap file.  On my system, there was already a swap file in use.

chumby-XX-XX-XX:~ # cat /proc/swaps
Filename                Type        Size    Used    Priority
/mnt/storage/.swap                      file        131064    1868    -1
chumby-XX-XX-XX:~ # free
              total         used         free       shared      buffers
  Mem:       125120       122748         2372            0         5080
Swap:       131064         1896       129168
Total:       256184       124644       131540

Here's how to make a new one:

chumby-XX-XX-XX:~ # dd if=/dev/zero of=/mnt/sd/.swap bs=1 count=0 seek=1G     
0+0 records in
0+0 records out
0 bytes (0B) copied, 0.000318 seconds, 0B/s
chumby-XX-XX-XX:~ # mkswap /mnt/sd/.swap     
Setting up swapspace version 1, size = 1073737728 bytes
UUID=12345678-1234-1234-1234-123456789012
chumby-XX-XX-XX:~ # swapon /mnt/sd/.swap
chumby-XX-XX-XX:~ # swapoff /mnt/storage/.swap
chumby-XX-XX-XX:~ # rm /mnt/storage/.swap
chumby-XX-XX-XX:~ # free
              total         used         free       shared      buffers
  Mem:       125120       116296         8824            0         6012
Swap:      1048568            0      1048568
Total:      1173688       116296      1057392
chumby-XX-XX-XX:~ # cat /proc/swaps
Filename                Type        Size    Used    Priority
/mnt/sd-12345678-1234-1234-1234-123456789012/.swap file        1048568    0

You should use .swap as your swap-file name.  The swap_activate.sh script looks for files named .swap during bootup.

Anyone ever add ram using a soldering iron?

  • Registered: 2010-08-13
  • Posts: 89

Re: Adding more ram

ryoohki wrote:

Anyone ever add ram using a soldering iron?

Maybe if we can locate the manufacturing company who makes the ram, we can get the exact model and find a bigger size (1 gb or more ) and make sure it has the same amount of pins on the chipset. Un solder the old and solder in the new.. Just throwing ideas out dont know too much about hardware

4 Reply by kevin.vermeer (edited by kevin.vermeer 2011-09-06 07:04:48)

  • Registered: 2011-03-24
  • Posts: 1

Re: Adding more ram

@Phoenixflames: Sounds like you've read too many stories of hacking phones.  Chumby Industries is very much more open than that!

The hardware specs (http://wiki.chumby.com/index.php/Hackin … asic_specs) and schematic say that the memory is DDR type RAM in a 66-TSSOP package running a 16-bit bus with a minimum speed grade of 166 MHz/6ns.  Memory interfaces are well-standardized by JEDEC (also a comparatively open company), so you can probably plug those stats into any distributor and find parts to purchase.

When I did this, I found that there are quite a few compatible 512 Mb (64 MB)  parts, such as Micron's MT46V32M16P-6T:F for $11 in single quantities from Digikey.  Unfortunately, it seems that 512 is the ceiling for these parts.  The processor itself assigns a 512Mb per chip restriction, and the 1Gb version of the RAM (MT46V64M16P-6T:A) is $90 each, out of stock, and only available in 1,000 piece lots.  If you find a 1Gb or larger variant available in small quantities at a reasonable price that works with the processor, let us know!

Otherwise, you're looking at adding a second RAM chip.  The processor is designed for this, but the PCB doesn't have a second footprint for this. Fortunately, it does have the second chip select line broken out to J112 (On the bottom, between the MicroSD card and bar code). Alternatively, hit this via: http://i.imgur.com/Lfkhc.png from the top if you don't want your wire to have to run around the edge of the board) You'll have to stack the two ICs, and you'll have to duplicate the CS circuitry: A 22 ohm series termination resistor and a 47k pullup to 2.5V, connected to Pin 24 of the memory IC. Good luck!

(Note: Any advice from someone with more knowledge of memory interfaces and whether the above would work is greatly appreciated!)