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I am starting to have a need for more memory.. Ethercard, Graphicscard they all need lots of PROM and RAM
is there a sollution for I2C ram/dataflash ? (a new plug ?!) perhaps even combined with an SDcard interface to store more website data (.jpg or even .mp3) and more RAM to get it into the world ?!
the SDcard can also be an easy way to get graphics/website data into and measurement dat out of a JeeNode
I feel your pain... I too wish there was a way to hang a DIMM on the side!
Unfortunately the address and data bus required to add RAM aren't brought out on pins and Eeprom/SDcard are very slow compared to RAM. The processor can only act on the data once it is in RAM so you'll need to swap things in and out as required... Like a Windows machine with 32meg of RAM and it's hard drive swap file, painful.
The other option, which I have in mind at least for the graphicscard is to dedicate an ATmega to doing just the graphics. Any extra functions, processing etc are carried out by a main JeeNode, which sends screen update instructions to the JeeNode running the graphicscard. A GPU in effect - or as JC said elsewhere JeePU (I'm still kicking myself for not making that joke first!). The JeePU takes the 1K memory hit for the screen leaving the main node free to do whatever you want it to.
Alternatively we could always try to talk JC into fitting an ATmega2560 to a JeeNode, although I don't think it will fit (large hammer maybe required!).
Yep - of all on-board resources, RAM is usually the most constrained one.
It's possible to add an SD-card interface, but SD cards and µSD cards are very slow (as seen from an ATmega). Adding a slow device on the SPI bus is inconvenient, because it'll interfere with the RFM12B radio.
Flash memory as included in the JeeLink is a lot faster, but not all models support per-page erase/rewrite, so it may affect how you can use 'em.
RAM is not a practical option - besides, it's volatile. Still, I'd like to create an interface for it one day - if only to re-use all those SDRAM sticks I've swapped out of various notebooks over the years...
The main reason I've not worked on a solution yet, is that I don't know which approach would work well - if any. There is a Memory Plug, which should work fine for website page storage and as small datalogger.
I'm open for suggestions. Meanwhile, I'll keep looking for a way to get rid of that tcp/ip buffer in the EtherCard library. It needs a major rewrite, but since the card itself has 8 Kb, it really is should be possible to get rid of it. The trick is to not generate a complete packet in RAM first.
You can get some 112 bytes extra when you change the RXBUFFER to 16,serial port will work fine at 9600.
=>hardware/arduino/cores/arduino/HardwareSerial.cpp
change #define RXBUFFERSIZE 128 to 16
Mostly when the ram gets < 450 weird things can happen.