Lpc2000

> From: "Leon Heller" <leon.heller@...>

> I think that is probably the case, contrary to what I said
> earlier. Ground bounce due to poor construction techniques may be
> one reason why some people have problems getting it to work
> reliably.

Some PC printer ports generate fast (<10ns) spikes of up to 1 
volt amplitude on some pins. They can be very difficult to 
remove, and will often trigger buffers that have TTL threshold 
levels. Most printer ports now run at about 3v and if the device 
is powered through the printer port, it is probably operating 
way outside its datasheet specs.

Stephen

> 
> Leon 
> 


--
Stephen Pelc, stephen@...
MicroProcessor Engineering Ltd - More Real, Less Time
133 Hill Lane, Southampton SO15 5AF, England
tel: +44 23 80 631441, fax: +44 23 80 339691
web: http://www.mpeforth.com - free VFX Forth downloads