[En-Nut-Discussion] ethernut board 3.1 LCD support

[Ulrich Prinz]

Hi Paul,

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 
bild fails.
- 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:
> Hello,
>
>
> 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
>
>   greetings
> Paul Govers
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