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SubjectRe: [RFC] new 7-segments char translation API
On Wed, Jun 01, 2005 at 02:33:11PM +0200, Clemens Koller wrote:
> Hello, Henk!
>
> >1 - Notation
> >
> >Make things potential interoperable, your character sets will be
> >portable to other LCD devices.
> >
> > +-a-+
> > f b
> > +-g-+ => encodes to => MSb 76543210 LSb
> > e c gfedcba
> > +-d-+ bit7 is reserved.
> (x)
>
> Bit7 is propably useful for the decimal point (x)?
> Well, that's how I used it some time ago.
>
Hi Clemens,

I think it could. However for conveniance I implemented it as a
seperate addressable entity.

For userspace I want things to be simple, just a simple echo should be
sufficient to manipulate the LCD:

For example:

echo -n "3 A 1.0 0 0" > /sys/.../line1

in order to set the lcd. In order to read back the contents of the lcd:

cat /sys/.../line1
8.8.8.8.8.8.8.8.888 <= format string, see below
3 A 1.0 0 0 <= contents


When the dot is encoded in the digit you would lose a digit when a
dot is printed. In a two segment display with dots "1.0" can not be
printed.

I don't want kernelcode trying to decide if it should collapse "1." in
a single digit or not. These implicit functional rules are always a
pain in the ass when not implmented at the right level. And don't
belong in the kernel.

Best regards,
Henk


/* Format string description:
*
* From a user space perspective the world is seperated in "digits" and "icons".
* A digit can have a character set, an icon can either be ON or OFF.
*
* Format specifier
* '8' : Generic 7 segment digits with individual addressable segments
*
* Reduced capabillity 7 segm digits, when segments are hard wired together.
* '1' : 2 segments digit only able to produce 1.
* 'e' : Most significant day of the month digit,
* able to produce at least 1 2 3.
* 'M' : Most significant minute digit,
* able to produce at least 0 1 2 3 4 5.
*
* Icons or pictograms:
* '.' : For example like AM, PM, SU, a 'dot' .. or other single segment
* elements.
*/

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