Memos From the Cube

Today I received a rather nice email from fellow AVRFreaks member Collin O’Flynn. In part:

Hi Dean,

I ended up getting RNDIS support to work on the Atmel USB chipset.

I used the Atmel application note as a base, due to the fact that you need a
lot of other crap for this to be useful. Other crap means TCP/IP stack of
course… and the Atmel application note was a bit easier to integrate
beacuse of this.

But I’m trying to get the code to interface to Linux now, as Linux does have
RNDIS support and should have working IAD support….

That’s rather neat – it means that a working RNDIS implementation is possible on the USB AVRs. I’ve been ITCHING for something to do the last two days, so I’m jumping in and cooking up my own implementation. Everything is from scratch — I’ve re-downloaded the RNDIS specification once again and started coding, basing the demo on the existing CDC MyUSB demo. Hopefully I’ll be able to make a working implementation on top of MyUSB without the use of any RTOS or dynamic memory.

I know I originally discounted the idea of Ethernet over USB due to the three competing standards (two of which are USB-IF certified, and once of which – RNDIS – is a Microsoft abomination) however since it appears that Linux supports it I can’t see the harm. In any case, it’s a sad fact that the majority of systems run Windows. And let’s face it, it’s many magnitudes more likely that Linux will implement RNDIS (quckly!) than it is that Microsoft will implement one of the true CDC Ethernet standards.

So far I’ve got my implementation to enumerate and show up in the Network Connections screen of my laptop, although the interface is currently dead (disabled permenantly) until I implement all the mandatory control commands and start sending some data.

I’m also excited to learn that the first 1000 board run of Donald Davis’ “Benito” Arduino programmer boards is going ahead. Excited because it’s the first large scale production of a device (to my knowledge) running MyUSB! If your project runs on MyUSB, please don’t forget to send me an email!