This little project is looking good. I'm wondering about the complexity of soldering the 100 pin cpu by hand, has anyone here done this before? if so, what solder diameter did you use with what kind of tip?
Smallest you have, or better: solder paste and a stencil.
http://www.proto-advantage.com/store/product_info.php?products_id=2220251
or this one
http://www.proto-advantage.com/store/product_info.php?products_id=2220161
check the body sizes.
Thanks Crossroads.
Another question: the schematic uses a 20mhz crystal (see attached image), and my standard Arduino mega uses a 16mhz resonator. I'd like to keep it running at the standard frequency to maintain compatibility with interrupt driven code that will run on it. I've looked at the 2560 mega example that comes with Eagle but am still unsure. What do I need to change in my schematic?
1.bmp (720 KB)
j514:
What do I need to change in my schematic?
Use the Value command and change it to 16Mhz.
You could just blank out the value - that's a choice you can defer till you build a board.
I concur with either approach.
Great success!
The mcu was drag soldered with a standard chisel tip at 440 degrees, then cleaned up using solder wick. A 15x magnifying loupe was necessary to see what was really happening.
Thanks to everyone here who helped make it possible, especially codlink, Crossroads and Nick Gammon.
Soldering tutorials that made a difference:
edit: resized image & links
Looks good! But the true test is how it performs. I think your soldering job looks better than mine and I use hot air with paste for my SMD work..
So far I haven't noticed any performance change from my standard arduino mega. The first boards were built a few weeks ago, today they were made photogenic after a bath in isopropyl alcohol. That excess flux really makes for ugly pics! Uploading with the isp is easy, and the project power requirements have gone way down thanks to a bunch of tweaks. I haven't run through a set of batteries yet with the touchscreen disconnected, otherwise she lasts for about 12 hours with the screen connected and on at full brightness.
This stuff is like porn. Can I say that?
This stuff is like porn. Can I say that?
Sure - we'll know it when we see it 8)
Nice job on the assembly.