Date   : Mon, 06 Aug 2007 14:03:23 +0100
From   : dominic@... (Dominic Beesley)
Subject: Emulating Econet hardware?

----- Original Message ----- 
From: "Jules Richardson" <julesrichardsonuk@...>
To: <bbc-micro@...>
Sent: Monday, August 06, 2007 12:59 PM
Subject: Re: [BBC-Micro] Emulating Econet hardware?


> Alex Taylor wrote:
>> Hi
>>
>> Here's a completely random thought after reading a previous post.
>>
>> Would it be possible to emulate an Econet server and clock using a
>> PC's parallel port, and suitable software and cabling?
>
> I think the last time this came up the general feeling was that yes, it 
> could
> be done - then things got bogged down with too many people starting a 
> flamewar
> about how parallel ports are obsolete, and that this should be done with
> FPGAs/USB/FireWire/ExpressCard instead ;-(
>

Some while ago I got a basic clock box and started work on an idea for
an econet to usb pic project. As stated I found that the original Motorola
chips were a bit tricky to obtain. There seemed to be a few though that
could do some of the encoding and crc checking necessary.

I'm flat out working at the moment but towards the end of the year I am
hoping to go back and improve on this and will keep the group updated. If at
all possible I'll probably try and keep the design to a handful of PIC
uControllers as these are cheap, readily available, easy to program (both
in terms of software and hardware) and increasingly fast

To answer the original poster the clock should be a doddle, though I'm not
sure you'll be able to go to econet full speed, last I looked access to the
parallel port was quite slow on my modern motherboard and any high speed bit
banging seemed to introduce a lot of FSB->PCI->ISA wait states (or something
I'm not overly up to speed on PC hardware) and the machine ground to a halt.

I got more joy bit banging the serial ports!

Cheers

Dom