Some NanoNote Hardware Experiments

Paul Boddie paul at
Sat Jun 1 13:29:06 EDT 2013


Werner's statistics round-up has once again prompted me to post to the list. 
This time, it's about some experiments I have been doing with the Ben's 8:10 
port, with the Universal Breakout Board (or equivalents) being used to 
interface to various devices.

First off, some work to interface with an Arduino USB Host shield:

Since such shields can provide USB Host capabilities to devices like the 
Arduino Duemilanove, it's not too surprising that they can do so for the Ben 
as well, although the Arduino's ATmega CPU provides hardware support for SPI, 
which is the mechanism used to talk to the shield's MAX3421E controller, and 
thus the Arduino is actually more capable than the Ben in this respect.

So far, I've only really managed to replicate some of the capabilities that 
the Arduino libraries provide, but basic communication is in place, and it's 
possible to get information from devices and to manage connections and 
disconnections. Managing the different USB workflows and supporting things 
like the Human Interface Device framework is tedious work, and the next step 
might reasonably be supporting this hardware as a kernel module instead, 
delegating the tedious stuff to code hopefully already written.

Another thing I got to play with recently was an e-paper display module using 
a screen from Pervasive Displays:

There is documentation and code available for displays from this vendor, and 
it seems that they are trying to get people to use their equipment. (Given 
that I've seen e-paper displays as shelf pricing labels in at least one 
supermarket, they may be getting somewhere.) I'm not sure whether my display 
module is open hardware, but Adafruit do seem to sell a similar module which 
might well be.

Neither of these projects are necessarily practical, and they may not inform 
us very much about hypothetical future NanoNotes. For USB, one would choose a 
SoC with built-in USB Host support which is exposed to the outside world; an 
e-paper display is useful as a secondary screen, but would be frustrating as 
the primary screen for this kind of device. Nevertheless, they do provide 
some experience with the technologies involved and help us decide whether 
they would be worthwhile supporting in future.

I hope this is interesting to some of you, at least.


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