Wednesday, June 25, 2014

Atmel Atmega1284

I started tinkering with the Atmega1284. Among other things it gives you an expansive 16kb of SRAM, 2 uarts and of course looking at the chip a bunch more IO. A huge plus is that you can get a nice small SMD version and this 40 pin DIP monster with the same 1284. Yay for breadboard prototypers who don't oven bake each board configuration! The angle of photo seems to include the interesting bits. Just ignore the two opamps on the far right :)

I had trouble getting this to work with a ceramic resonator. The two xtal lines are right next to each other with ground just above but the 3 pins on the resonator were always a bit hard to get into the right configuration for these lines. Switching over to a real crystal and 22pF caps I got things to work. The symptoms I was having with the resonator included non reproducibility, sometimes things seemed to upload sometimes not.  Also, make sure the DTR line is going though a cap to the reset pullup resistor. See the wiring just to the right of the 1284.

I haven't adapted the Arudino makefile to work on this yet, so unfortunately I still have to upload programs using the official IDE. I have the makefile compiling for the 1284 but das blinken doesn't work when I "make upload".

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