Re: [lcd4linux] driving a TC6963 via USB?

[Till H. <ti...@ha...>]

Hi,

On Sunday 12 February 2006 12:36, Michael Reinelt wrote:
> I have no idea, but I think there's not much of a difference. I' expect
> the CPU load to be lower with USB.
Exactly. USB can be quite fast, but most simple devices aren't. E.g. my 
display transfers at most 4 bytes per USB-Transfer. The USBLCD and WBCT
interface only transfer single Bytes. USB devices can transfer much more bytes 
per tansfer, but for my soft USB solution it would have increased the 
complexity and the current solution is just fast enough, so i had no reason 
to do more.

The current code is fast enough for the text LCDs and since the PC does most 
of the USB stuff in hardware there's nearly no load on the PC whereas the 
printer port solutions require plenty of io port accesses per byte and do 
some busy waiting in the kernel which does have some small performance 
impact.

> Till has developed a cheap DIY interface for HD44780 displays. If you
> got a spare T6963 display, maybe he will adopt his interface...
Or you take my project and use it to build such an interface yourself. This is 
"open hardware" ...

Till

-- 
Dr.Ing. Till Harbaum <ti...@ha...>
http://www.harbaum.org/till