Lpc2000

--- In lpc2000@yahoogroups.com, "onceinfour" <mmack287@h...> wrote:
> I suppose this is for the Philips Apps. 
> OK all pins except a/d are 5V tolerant.  What level (in the high 
> state) will I get on a pin configured as an output if I have a pullup 
> to 5V, and what current will it draw.  Sorry to harp on, but I need 
> to know what voltage level I can generate for my peripheral device, 
> and what size of pull-up I can use.

I have two observations for you.  

1) If you use a pullup, your output should be configured as open
collector or open drain (depending on your nomenclature preference). 
This is done by writing a '0' to the output data and controlling the
output drive (on/off or input/output).  

2) The data sheet for the UDN2981 says it is TTL compatible.  That
means the input switching level is between 0.8 and 2.0 volts, so you
don't need a pullup to 5 volts.  

Does that help?