[En-Nut-Discussion] ethernut board 3.1 LCD support
uprinz2 at netscape.net
Wed May 5 20:34:59 CEST 2010
yes, I am working on the LCD support for ARM. I am working on a lot of
display support, but I found out really fast that it doesn't make sense
to just add another driver. As it is difficult to do all at once and I
sometimes like to do some small projects to have success in a few
evenings, I started with the small drivers.
HD44780 is the first one.
Trouble targets that I already identified are:
- It interferes with the ST7036 drivers as both use same defines for
configuration. If the latter is configured in your conf-file, the first
gets overwritten. If you delete the defines from the second one, the
- Interface timing is problematic as it uses fixed loop counts of
numerous _NOP(). This is difficult as one has to manually trim this
loops for the dedicated hardware
- NutMicroDelay is not brilliant to, as the way it is trimmed at system
startup introduces a lot of variance too.
As a HD44780 is a more or less slow interface, I actually base the
rewrite on NutMicroDelay and accept that the timing is half at least
half as fast as it needs to be. After releasing the driver I will
optimize NutMicroDelay() if no one other did before. (It's not that
simple as it has to be written in assembler.)
The things with HD44780 are a bit weired. The scope says, the setup and
data is ok but the display says nothing or just character-salad. May be
I should release the driver as a Scope-Display for geeks who read binary :)
Best regards, Ulrich
Am 05.05.2010 12:04, schrieb Paul Govers:
> I want to connect an lcd 4x40 display to an ethernut 3.1 board, but many
> things have changed from ethernut 2...
> i found an manual: enan001.pdf with information about
> how to connect an lcd display to an ethernut board, but i think this is nut
> for an ethernut board 3.1
> Harald already has replied on my question and he let me know that Ulrich Prinz is currently working on LCD support for ARM. i was wondering when LCD support for ARM will be included in ethernut?
> (my display controller=hd447080 )
> many thanks
> Paul Govers
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