Re: AW: [Lcd4linux-devel] USB based hd44780 units ...

[Michael R. <re...@eu...>]

Hi,

> There's a nice project to do software bit-banging usb with atmel avrs
> (http://www.obdev.at/products/avrusb/index.html).

I had a look at this stuff, sonds very interesting!

I don't know much about USB and/or AVR, but I read that things are very
timing-critical. Looks like the 12MHz of the AVR are very tight, one has
to use every single available cycle just to read the bits from USB. I
wonder how the AVR shoud handle the display, too?

> I do understand, that the other usb adaptors are sold with few different 
> display types only. But i'd like to use as much different display as the
> generic hd44780 driver does. I am still not convinced, that having a
> seperate
> usb driver doing much of the same things the generic driver does (e.g. 
> adopting the addressing scheme for 16 col displays) is a clever thing ...
See my other mail. I agree with you. But I'm still unhappy with the
complexity of drv_HD44780.c There are so many things which are used with
the parport only (4/8 bit mode, busy-flag checking, all the timing
stuff, ....)

For the development of the hardware, I suggest using a seperate driver
like the BWCT. If we know that the hardware and the driver work, we can
integrate it into the HD44780 driver.


bye, Michael

-- 
Michael Reinelt <re...@eu...>
http://home.pages.at/reinelt
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