What a mess 3

["Arne Chr. Jorgensen" <instel-at-online.no>]

Hi,

I have little time just now, - but will add a few words.


Key switch > KB controller > platform Bios >  linux >terminal > tk/tcl > EMC 
 
Here is part of the situation:

You hit a key switch:

The KB controller will output code according to mode and model.
The platform low-level interface with the keyboard interface, could be Bios
related, etc. 

These two levels, can change the way any switch or sequence will be coded.

Linux is another level,  then "terminal".

Terminal is not any "standard" - it may be called an ANSI terminal, but that
is not a defined standard. The X lib and all other libraries, will do some
code "fiddling" .  Often they say an Xterminal is a VT100 emulator, but it is a
mix of VT100, VT102, VT52, etc. 

Then say a program language like tk/tcl may interpret this more like a VT52,
than say a VT100, and will tweak things a bit.  Then comes the EMC code.

The arrow keys is interpreted with escape codes, and all such codes, may be
interpreted a bit different, - say which library, linux version, etc. is used.

This is why I called the situation a "mess" - who really knows what goes on ?

That is part of why I raised the earlier question.

Operators panel:
-----------

By doing this our own way - we could avoid some of these problems.  I said you
could use the serial port, and you might. But you would have to choose a device
driver, that will not treat it with any terminal emulation.  

If you machine a part, then - here is my lack of experience. I have more or
less just worked with one kind of machine.  But this had a feed-rate over-drive
dial, so you could manually change the speed. Else you would need a control
loop to the G-codes, telling what feed-rates is right at a given moment.

Game port:
--------

This is something I have said a few things about before. Fred has written a
driver for joystick control in EMC.  Maybe we could do something with this ?
It could be called and read in a real time module.  It can be expanded to as
many switches you would like. ( Just send the code to me, and I will have a
look at it )

Several has said that the "analog" inputs is not reliable. Not so. With a few
electronic components, you could have a good analog input. (Use current control
instead of voltage control ) 

The idea is that this could be used as the interface for our keys, and have a
analog feed-rate dial.  ( you don't need to use  joysticks )

This could be a nice add-on for step motor drive.  Cheap, our own controlled
software and key interpreter. It could run in real-time mode, as a back-input
device. 

Comments ??

//ARNE