[Coco] Ethernet update

[James Dessart]

On 25-Aug-04, at 11:02 PM, Mark Marlette wrote:

> Can you explain how arrived at "and it works" for us?

Yes, I'll do that here. :)

> What is the OS platform?  What software was involved in the "and it 
> works" part of the test? What protocols are supported, how many 
> sockets?

There is no OS, it's simply the TCP/IP stack and a small sample 
application. This is compiled for the ATmega8 (although it should work 
on any AVR with enough IO pins). The test application is a small server 
that listens on port 1234 and returns the string "ok" whenever it gets 
input. I put the server on my local network, connected to it from my 
desktop using telnet, then sent some data.

Parts needed if anyone wants to repeat the test are an:

- AVR processor (such as the ATmega8)
- EDTP.com PacketWhacker
- 5V power supply (I use an LM7805A, 4 AA batteries and a 0.47 uF cap)
- uIP-AVR 0.60.1 (or if you have a 16K flash AVR, you can use the more 
recent version)
	available at http://www.laskater.com/projects/uipAVR.htm and written 
in C
- 47k pullup resistor on the RESET\ pin
- AVR programmer

After compiling the uIP-AVR code with avr-gcc, I programmed the chip 
using an AVRISP (a serial programmer). I needed to massage the code a 
little to accommodate the small number of IO pins on the chip (the 
mega8 only has 3 IO ports, whereas the AVR used originally had 4), but 
there are enough pins for the PacketWhacker. I breadboarded the whole 
thing, took me a bit of time, as I had to strip the ends of the wires 
too, and cut them to the right length.

Once it was assembled and programmed, it was just a matter of plugging 
it into my local network and connecting to it. I left the oscillator at 
the factory defaults, so it was running at 1 MHz.

My next step is to build a prototype card for the CoCo, and make 
modifications to uIP AVR so that the code will work on the CoCo with my 
interface. I mainly set up the AVR to test that I assembled the 
PacketWhacker well, and that I didn't have any really bad solder 
joints. My soldering is amateur, at best, I guess I just need more 
practice.

James