Re: Low-level help needed with leds

From: Abraham vd Merwe (abraham@2d3d.co.za)
Date: Tue Oct 30 2001 - 07:54:30 EST


Hi david.heremans!

I browsed through linux/drivers/char/pc_keyb.c and linux/drivers/keyboard.c
and it doesn't seem like it's caching sets/gets. I quickly browsed through
your code, but I didn't really look for errors. Instead, I hacked a quick
program for you which does exactly what you want. I don't have an ipac, but
I tested it on my PC (just pressed the keys, etc.) and it should work. If it
doesn't you should check the datasheet and see whether there shouldn't be
any delays between settings the leds.

PS: The program is attached

> I'm writing to this maillinglist as a last resort, since reading books
> and other peoples code didn't solve my problem, and it is on the vague
> boundary of userspace/kernel.
>
> I recently got hold of a nice little piece of hardware that must be
> connected between the computer and the keyboard. You can program this
> device by sending it bytes trough the keyboard-leds.
> More about this device at http://www.andywarne.pwp.blueyonder.co.uk/,
> the device is called the I-Pac.
>
> The programming protocol description I got from the maker of this hardware states this
> sequence.
> 1. Set any led combination execpt all leds on.
> 2. Send five times all leds on.
> 3. The I-Pac will send a key-down code for the 'Y' (ready to program) or
> 'J' (jumper set to fixed) key.
>
> I don't get this key code back.
> I was wondering if I misunderstood the way the Linux kernel sends this
> LEDs commands. Does it send extra led commands that I don't know about?
> Maybe it doesn't send twice the same led formation since it would be a
> logical optimisation? Honestly, I'm completely clueless by now, and
> digging into the Linux source code is way to complicated for me, I
> honestly tried but got lost in it (tasklets et all) :-(
>
> I took the liberty of attaching a simplified version of
> my programming tool. If some of the more knowledgable people here could
> please help me out, thanks.
>
> Sincerely,
> David Heremans
>
> PS: I'm not subscribed to this list, I just scan the archieves and
> digests from time to time. So I you reply please put me in CC.
> PPS: When compiling the c program I also got redefine warnings in
> headers, sugestions to solve these are also welcomme, the include list I
> use is a mix of other example programs, so I'm not sure which are the
> exact ones to use.

> -rw-r--r-- david/david 3131 2001-10-16 09:47:33 console-lib-program-ipac.inc
> -rw------- david/david 3491 2001-10-16 22:28:02 program-ipac.c

-- 

Regards Abraham

Work is the crab grass in the lawn of life. -- Schulz

__________________________________________________________ Abraham vd Merwe - 2d3D, Inc.

Device Driver Development, Outsourcing, Embedded Systems

Cell: +27 82 565 4451 Snailmail: Tel: +27 21 761 7549 Block C, Antree Park Fax: +27 21 761 7648 Doncaster Road Email: abraham@2d3d.co.za Kenilworth, 7700 Http: http://www.2d3d.com South Africa



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