> > > CTS is the pin the PC (DTE) pays attention to (input) for hardware
flow
> > > control.  CTS is generated (output) by a modem?(DCE)  RTS is generated
> by
> > > the PC (output) and monitored by the DCE device (input).
> > >
> > > BTW, hardware flow-control does NOT guarantee that no data overruns
can
> > > occur.  Hardware flow-control still depends on software to interpret
the
> > pin
> > > indicating the FIFO is full and to set the appropriate (RTS)
indicating
> > that
> > > no more data is desired.
> >
> > True, but in the case where the PC is transmitting data to the PIC, the
> PIC
> > can shut off the data flow from the PC by holding the appropriate
> handshake
> > line inactive. This physically prevents the USART on the PC from
> > transmitting (as long as it has been initialized to use hardware
> handshaking
> > of course...).
> > /\/\/\/*=Martin
>
> But, as I posted earlier: it does not. After the interrupt caused by the
> control line change occurs no additional characters will be written to the
> PC's UART. However any characters still remaining in the PC's transmitter
> shift register, buffer, or FIFO will still come blasting down the wire.
This
> could be quite a few characters with deep FIFOs.

OK, I see...then you also have to program the PC to not use the FIFO...it
does seem a bit silly to use a FIFO on the output if you need to be sure
that all the characters are accepted at the other end.

/\/\/\/*=Martin

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