Re: [CAD_CAM_EDM_DRO] fire and forget was Re: Black box again

Alan Marconett KM6VV wrote:

> Hi Ballendo,
>
> OK, I get it. But SPP (Standard Parallel Port) doesn't do that for you,
> at lest for type 1 (IBM). Type 2 or 3 (IBM DMA) might. Aren't you
> thinking of EPP (Enhanced Parallel Port)?

A total muddle! There are so many versions of these so-called 'specs'
that it is a real mess. You have to try all the BIOS settings of the
port to find out which one works! Well, you can write a byte to a
SPP port in one instruction, without handshaking, but that is not
a very practical communications protocol.

EPP does allow you to do that, but there are several versions of the
spec. The 1.7 is not really done right, but the 1.9 version seems to
have a decent handshaking protocol. Then, there's the DMA
block transfers to make things really messy. but, the 'messages'
for real time axis control are too short to make DMA very practical.

Jon