Flash Memory Extensions


I am using the Ethernet Arduino board, so the flash memory is 32kb, but my program is 40kb,and I can't reduce it. So i'd like to know, if it's possible to use an external flash memory.


No. Need to move to a bigger chip, such as 1284P with 128K flash, or 2560 with 256k flash. You can pull the processor and wire a 1284P chip in parallel. One of my first projects back in late 2010, early 2011, was doing just that. Browse the forum for "hacking the Uno!" for a topic I started on that.

See here http://forum.arduino.cc/index.php?topic=56567.0 Used the SPI and Serial connections from the Uno, wire wrapped the other IO directly. Similar can be done with Ethernet board.

http://www.onsemi.com/pub_link/Collateral/CAT811-D.PDF Unfortunately ethernet arduino uses SMD chip. Was thinking perhaps tie Reset low to disable the '328P, but that also Resets the ethernet chip. If you remove the CAT811 chip, can seperate the 2 resets and then connect in a 1284P to the Digital and Analog pins.

Looks like IC1 is next to the 25MHz xtal, decent size pads to work with for adding in your own Reset connections.