/*
 *
 * ceddrv.c -- a driver for CED 1401 laboratory interface
 *
 * Copyright (C) 1995 Georg v. Zezschwitz
 * Copyright (C) 1995 Alessandro Rubini
 *
 *                    zezschwi@kogs26.informatik.uni-hamburg.de
 *                    rubini@ipvvis.unipv.it
 */

#if 0 /* only yo justify the comments above ;-) */


    What's this?
    ------------

The CED 1401 is a laboratory interface providing 16 to 32 ADC-Chans, 4
DACs,  24 digital I/O  lines and several event  timers and clocks.  It
has its own processor and memory and is supported by several Macintosh
and DOS programs.

This code enables Linux 1.2 to read and write to  an 1401 provided the
right ISA-card is attached.

Hopefully, no changes to the kernel are needed.

This device driver is conceived as a module, and it should be compiled
under the same kernel which will be used to run it. The ced device can
then be used through the node /dev/ced0.

The major  device number is generated  dynamically; thus the /dev node
must be recreated after each module loading. This is no problem, since
the module can only be loaded by root.


    Language interface
    ------------------

This package  embeds  a C library,  to  ease handling  the acquisition
board.  The documentation *will_be* available in "info" and postscript
format.  Public symbols and definitions are prefixed in this way:

 Ced_   for functions, global variables (if any) and data types
 CED_   for preprocessor defines
 _ced_  for global variables within the library.


    Multiple devices
    ----------------

The module supports multiple devices (up to four of them). They can be
accessed through the    device  nodes called  /dev/ced0,    /dev/ced1,
/dev/ced2 and /dev/ced3.

However, since each of us  owns only one 1401  device, the feature  is
untested.


    Compiling and installing
    ------------------------

A simple  "make" invocation will compile the  module, the  library and
the test programs. A "make install" will install  things in the proper
places,     i.e.      /usr/local/bin,       /usr/local/include     and
/usr/local/lib.  The module is installed in /lib/modules/VERSION/misc,
where VERSION is your current Linux version.

If your kernel doesn't have it already, the symbol "mem_map" should
be exported. Refer to the doc files.


    Loading the module
    ------------------

To load the module  issue "ced_load"; the script  is a  simple wrapper
around "insmod"   which  created the  /dev  nodes after   loading  the
module. To  unload  the module  issue "ced_unload";  the script  is  a
simple wrapper around "rmmod" which removes the /dev nodes as well.
The following variables can be set when loading the module:

ced_base   Can be used to select an I/O base address. Disables autodetection
ced_major  Select a device major number. Disables dynamic allocation
ced_fake   Allows a developer to load the module if the board is not there.

For example  "./ced_load   ced_base=0x340 ced_fake=2".



    Remarks
    -------

We recommend using  Linux 1.2.x. The driver  is untested with previous
kernels.  Linux 1.2.x has to be modified slightly according to the
documentation. Kernels since 1.3.7 should directly support it, but 
remember they are experimental :-) (Well, our stuff is momentary, too)

Enjoy, but remember that the whole thing is under development.

		Georg v.Zezschwitz, zezschwi@kogs7.informatik.uni-hamburg.de
		Alessandro Rubini, rubini@ipvvis.unipv.it


#endif /* Nice, isn't it? */