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LPC2148 and UART with hardware handshaking

Started by Gus January 13, 2006
Hello,

Is it possible enable TX,RX,CTS and RTS on UART1 on LPC2148 (with HW
handshaking) while using the rest of UART1 pins as general purpose
pins?

Thanks,

Gus



An Engineer's Guide to the LPC2100 Series

At 05:49 PM 1/13/06 +0000, Gus wrote:
>Is it possible enable TX,RX,CTS and RTS on UART1 on LPC2148 (with HW
>handshaking) while using the rest of UART1 pins as general purpose
>pins?

The short answer would be yes.

The longer answer is to ask 'What are you expecting that to do?'

If you expect the handshake to take place automatically then no. The
status and control pins on UART1 must be driven and read by the SW as
appropriate. In fact the only advantage really is that the status pins
will provide an UART based interrupt. The control pins have to be set by
the SW when you want them to change. It's the standard configuration in
that family of UARTs since the 8250 when they were added mainly so that a
single chip could handle the whole serial port.

Robert

" 'Freedom' has no meaning of itself. There are always restrictions, be
they legal, genetic, or physical. If you don't believe me, try to chew a
radio signal. " -- Kelvin Throop, III
http://www.aeolusdevelopment.com/


---- Original Message ----
From: "Robert Adsett" <subscriptions@subs...>
To: <lpc2000@lpc2...>
Sent: Saturday, January 14, 2006 6:46 AM
Subject: Re: [lpc2000] LPC2148 and UART with hardware handshaking

> At 05:49 PM 1/13/06 +0000, Gus wrote:
>> Is it possible enable TX,RX,CTS and RTS on UART1 on LPC2148 (with HW
>> handshaking) while using the rest of UART1 pins as general purpose
>> pins?
>
> The short answer would be yes.
>
> The longer answer is to ask 'What are you expecting that to do?'
>
> If you expect the handshake to take place automatically then no. The
> status and control pins on UART1 must be driven and read by the SW as
> appropriate. In fact the only advantage really is that the status
> pins will provide an UART based interrupt. The control pins have to
> be set by the SW when you want them to change. It's the standard
> configuration in that family of UARTs since the 8250 when they were
> added mainly so that a single chip could handle the whole serial port.

The UARTs in LPC214x and LPC2101/02/03 actually have hardware auto-RTS and
auto-CTS flow control (and a fractional baudrate generator, and functions
that can help with baudrate detection).

Karl Olsen


At 11:25 AM 1/14/06 +0100, Karl Olsen wrote:
>---- Original Message ----
>From: "Robert Adsett" <subscriptions@subs...>
>To: <lpc2000@lpc2...>
>Sent: Saturday, January 14, 2006 6:46 AM
>Subject: Re: [lpc2000] LPC2148 and UART with hardware handshaking
>
> > At 05:49 PM 1/13/06 +0000, Gus wrote:
> >> Is it possible enable TX,RX,CTS and RTS on UART1 on LPC2148 (with HW
> >> handshaking) while using the rest of UART1 pins as general purpose
> >> pins?
> >
> > The short answer would be yes.
> >
> > The longer answer is to ask 'What are you expecting that to do?'
>
>The UARTs in LPC214x and LPC2101/02/03 actually have hardware auto-RTS and
>auto-CTS flow control (and a fractional baudrate generator, and functions
>that can help with baudrate detection).

I knew about the fractional generator but not the others. Nice. Thanks

Robert

" 'Freedom' has no meaning of itself. There are always restrictions, be
they legal, genetic, or physical. If you don't believe me, try to chew a
radio signal. " -- Kelvin Throop, III
http://www.aeolusdevelopment.com/