Chris,

thanks for your idea but couldn't understand clearly. what to do ?

Chris Eddy wrote:

> Russell;
>
> The send function in a UART is actually somewhat simple.  Assuming you
> have interrupts,

sorry I do not use interrupt for uart

> which is the real efficient way to do it, just bang
> your message out.

that is from transmitter right ?

> Then let the recieve run through the UART.

is this means connecting transmit and receive together ?

> The
> recieve is the real work.

if the receiver takes the data back then how am I transmit ?

> You said you wanted to invert the send,

yes transmit only

> not
> recieve.  If you want to do both, well, that is a different story.
>
> Chris Eddy
>
> Russell McMahon wrote:
>
> > Probably not I'd say.
> > BUT
> > To do it in software probably costs very little.
> > single NPN small signal transistor, emitter to ground.
> > 10k resistor from output pin to transistor base.
> > Resistor (size depends on drive required - 1k to 10K probably) from
> > collector to Vcc.
> > Output from collector.
> >
> >             Russell McMahon
> >
> > -----Original Message-----
> > From: Andre Abelian <engelec@earthlink.net>
> > To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
> > Date: Sunday, June 27, 1999 6:53 AM
> > Subject: how to invert hardware uart output in software?
> >
> > >Hi to all engineers.
> > >
> > >I am working with hardware uart 16c74a  I need to invert the uart
> > >output beside adding external inverter is there any way of doing it
> > >in software ? any help will appreciated.
> > >
> > >Andre
> > >

Andre