[sdiy] Multiple LCD connection sanity check please

[ChristianH]

You could save some time by having separate delay counters for each
dispay in your background process, so the wait periods can be in parallel.

In other words, if display A is waiting, you don't have to block display
B too until A is ready. Would probably need separate FIFOs for
each display however, otherwise it may get confusing to find out what's
still left to send.

Chris



On Tue, 11 Jan 2011 15:51:27 +0000 Neil Johnson
<neil.johnson97 at ntlworld.com> wrote:

> Hi Tom,
> 
> > I'm ok with that. Following advice I received here in the past, I've written a buffered LCD output routine. You can stuff long messages into a buffer, and then a background task sends a character to the LCD every 0.5mS. The only clever bit is that you can also send delays to the LCD buffer, which makes it easy to deal with LCD commands that take more than a single 0.5mS time period.
> 
> Well, if you have lots of displays then you'll presumably have lots of
> data to display on them?  In which case 2000 bytes/s may not be fast
> enough.  In principle you can send characters to the LCD drivers in
> sub 100us.  Some commands take longer (RETURN is typically >1ms).
> 
> > Failing that (simply paralleling them all up) I guess I'd be looking at adding a tristate buffer between the LCD inputs and the bus, would I?
> 
> You could probably get away without using tristate buffers, unless
> these were hanging off a system data bus.  I don't think that's the
> case here though.
> 
> > Well, 6 or 8 would be nice. Shall I give it a whirl and let everyone know how I get on?!
> 
> I guess it all boils down to your specific application, so yes do try
> it and let us know!
> 
> (BTW, little nitpic: capital-S stands for Siemens, the unit of
> conductance; seconds is small-s).
> 
> Cheers,
> Neil
> -- 
> http://www.njohnson.co.uk
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy