I was working on GPIO under Plan9 - very simple thing but also supports
edge-raising/falling events. I had simple C code to print what pin
triggered an event. I'll try to push this simple test to github during
weekend. Though i'm not sure how it can be integrated - is events counting
enough?

Krystian
https://github.com/elewarr/plan9-bcm

2014-05-08 20:36 GMT+02:00 Bakul Shah <bakul@bitblocks.com>:

> On Thu, 08 May 2014 18:58:31 BST "Steve Simon" <steve@quintile.net> wrote:
> > I have a hifiberry (http://www.hifiberry.com/) nicely minimalist,
> > though no driver at present - I will await the GSOC project :-)
>
> > I have some itron VFDs from work, 256 x 64 pixel. I like these as
> > the visibility is excellent. The only annoyance is they have
> > a parallel interface and I use up all the PI's GPIOs.
>
> > I also need to interface a rotary encoder for the tuning knob which
> > is also a pain - not complex enough to justify an FPGA, but a bit too
> > much to poll when the PI is doing audio decode as well.
>
> No need for polling.  The BCM2835 can handle edge triggered
> interrupts.  Or you can use a PAL or CPLD.
>
> > Thinking of adding a PIC or an AVR just for the encoder / VFD interface
> > and talking i2c to it.
>
>