Arduino Mega 512K SRAM in shield format
Some time ago now I presented the design, development board and software driver for an add-on to the Arduino Mega that gave it access to 448Kb of additional SRAM arranged in 8 banks of 56Kb.
My design was realised by a compact add-on board that plugged into the relevant block of pins on the end of the Arduino Mega.
Recently I have been in touch with a fellow hacker, Colin Irwin of langrangianpoint.net, who also has an interest in Arduino projects. Colin adapted my design into a full Arduino shield format and was kind enough to send me a kit of parts to evaluate.
Colin’s Design
The bare PCB follows the format for Arduino Mega shields. Colin has made it a little easier to solder straight connectors by adopting the slightly staggered holes popularised by the guys over at Sparkfun.
Building it
I did the build with what is now my usual technique. Firstly I tin the pads on the board with a soldering iron, then I reflow the fine-pitch components using a hot-plate and finally the discrete SMD components are reflowed into place using a hot-air gun. When it’s all done I inspect under a microscope and touch up any joints that look insecure.
Here’s the finished item plugged on top of my Mega 128. The shield completely covers the Arduino and you can only just see the USB port poking out from the side.
As I’m very familiar with the design I wasn’t expecting any problems and it proved just so with the board working first time.
Finally
Colin’s design represents a logical step forward from my original design. It feels very solid when built and plugs in firmly to the Arduino underneath. Anyone wanting to find our more or to get their hands on one of these shields should visit Colin’s website at langrangianpoint.net.