[dorkbotpdx-blabber] Simplifying the NES controller

[Paul Stoffregen]

> Hi party people.
> Could I possibly get this:
> http://www.zero-soft.com/HW/USB_NES/index.php
> to use a Benito instead?
>   

You most certainly could, with quite a bit of programming effort.  
Reading the shift register from the old NES controller is easy.  You 
could even use the SPI port to do it, rather than manipulating the pins 
directly.  That Konami code door lock project I made a while back used 
port pins, not SPI.  It was very easy.

The USB HID, and generic USB stuff is where almost all the coding will 
be.  There is an example HID implementation on Atmel's website, using 
the proprietary (expensive) windows-only compilers.  There's also a 
small matter of getting the HID and USB descriptors correct, which are 
the bytes your computer reads to auto-detect (or "enumerate" in USB 
lingo).  Fortunately, this is about the simplest possible HID config, 
where you have only one "report" that is just a single byte representing 
8 buttons (still, it's absolutely .  You could even just read the shift 
register when you get the interrupt "IN" packet, put that byte in the 
USB fifo and then set the 2 bits that case the AVR chip to send the 
response.  Very simple.

If you wanted to learn a lot of the gory details of how USB really works 
by doing about the simplest possible USB project, this would definitely 
be it!


-Paul