I've been using the Arduino Mega 2560 to run a physics experiment, controlling motors, servos, cameras, the low power lasers illuminating the setup, etc. I've been using Michael Margolis's O'Reilly book as a resource to find out how to get the complicated stuff done, like changing the PWM timers to get higher frequency resolution. I understand the basics like motor and servo control - having a Ph.D. in Physics makes that pretty straightforward for me.
It looks like the Due would be even better for this application (and it's not too late for me to switch over). 12 bit PWM and having two DACs that can provide "true" analog output (also at 12 bits if needed) are really nice. The faster clock and more powerful processor aren't critical, but couldn't hurt. The issue is that I can't find a book that will give me the same insights into how to customize and tweak the Due, like Margolis's book allows me to do for the Uno and Mega. And with Newegg selling them at $19 a piece, the price is really sweet.
Are those details the same? (I suspect not, different processor.) Is there a book that gets one into the guts of the Due? Or would I have to assemble the information piecemeal, as needed? Any advice appreciated.
And allow for the Due being 10x more complex... A lot more learning curve, basically.
However it is very logically put together - you spend hours studying the datasheet and
end up with 5 lines of code that both do the job!
The messiest thing is the port / pin / peripheral mappings, which to my mind spoil an otherwise
clean design. For instance of the 4 SPI chip select lines one isn't pinned out and the
others are pretty random. There's always a workaround though.
I'd give up on the DACs, they don't do the full voltage range and are 'sparkly' - add external
MCP4922's or audio DACs (WM8524?) for better performance. The Due board has no
separate analog ground
or power and suffers a lot as a result I think.
About the DACs, the voltage range isn't a problem - a single op amp can solve that. I'm more concerned with the step size, and consistency. What do you mean by "sparkly", MarkT? Plagued with excess noise from the digital artifacts of the rest of the chip? Would an extra cap somewhere on the board help with this? (We are hackers and makers, after all.) The board clearly wasn't designed as a DAC to take your CDs and produce audiophile grade analog output (if so, it would be a steal at 10x the price if it could deliver on that promise).
The linked data sheet is 1456 pages long (plus appendices, indices, and TOC.) Not a casual read while in the can, ....
I'll get started on this. Thanks for the info, and any other input appreciated.
aeronaut:
The board clearly wasn't designed as a DAC to take your CDs and produce audiophile grade analog output (if so, it would be a steal at 10x the price if it could deliver on that promise).
Have you seen the audio library and hardware I've been developing on Teensy?
It appears to have sparkle codes, hence sparkly. Not the worst sort, just 20 or 30 LSB
spikes. Although I'd have to go back and do some more research to investigate more,
I did de-solder one of the components on the board to allow the AREF pin to be externally
driven/decoupled I think, without curing the problem.