Forums

What is the UART CTI Interrupt?

Started by Robert Davis April 6, 2004
Hi,

I am working with the UART1 of the LPC2106 using the UARTecho sample program with the KickStart board from IAR. The UART keeps generating the character time-out indicator interrupt. I have looked through all of the documentation from Philips and I cannot find an explanation of what actually causes this interrupt. Does it mean that a stop bit was not found in nine bit times from the start bit? Does it mean that the receive FIFO overran? Is this lack of a clear and concise explanation indicative of Philips documentation? I am new to the LPC210x family, so please excuse my lack of understanding if the answer is obvious. I have worked mostly with Motorola micros and there documentation seems more concise.

Thanks,
Bob Davis




An Engineer's Guide to the LPC2100 Series

At 11:43 AM 4/6/04 -0400, you wrote:
>I am working with the UART1 of the LPC2106 using the UARTecho sample
>program with the KickStart board from IAR. The UART keeps generating the
>character time-out indicator interrupt. I have looked through all of the
>documentation from Philips and I cannot find an explanation of what
>actually causes this interrupt. Does it mean that a stop bit was not found
>in nine bit times from the start bit? Does it mean that the receive FIFO
>overran? Is this lack of a clear and concise explanation indicative of
>Philips documentation? I am new to the LPC210x family, so please excuse my
>lack of understanding if the answer is obvious. I have worked mostly with
>Motorola micros and there documentation seems more concise.

Philips defers to the 16550 documentation for detailed explanations. See
for example http://www.national.com/pf/PC/PC16550D.html#Datasheet or
http://www-us16.semiconductors.com/pip/SC16C550IA44.html

The CTI essentially means that there are characters in the receive FIFO but
not enough to pass the threshold and there are no characters coming in.

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


Bob,

take a look at the User Manual, p.89. Not too bad an explanation. ;-)

-uwe

----- Original Message -----
From: "Robert Davis" <>
To: <>
Sent: Tuesday, April 06, 2004 5:43 PM
Subject: [lpc2000] What is the UART CTI Interrupt? > Hi,
>
> I am working with the UART1 of the LPC2106 using the UARTecho sample program with the KickStart board from IAR. The UART keeps
generating the character time-out indicator interrupt. I have looked through all of the documentation from Philips and I cannot
find an explanation of what actually causes this interrupt. Does it mean that a stop bit was not found in nine bit times from the
start bit? Does it mean that the receive FIFO overran? Is this lack of a clear and concise explanation indicative of Philips
documentation? I am new to the LPC210x family, so please excuse my lack of understanding if the answer is obvious. I have worked
mostly with Motorola micros and there documentation seems more concise.
>
> Thanks,
> Bob Davis >
>
> Yahoo! Groups Links >



You are right Uwe. I missed it. It was right under my nose ;)

Thank you,
Bob Davis

--- In , "Uwe Arends" <Uwe_Arends@o...> wrote:
> Bob,
>
> take a look at the User Manual, p.89. Not too bad an explanation. ;-
)
>
> -uwe
>
> ----- Original Message -----
> From: "Robert Davis" <rdavis@I...>
> To: <>
> Sent: Tuesday, April 06, 2004 5:43 PM
> Subject: [lpc2000] What is the UART CTI Interrupt? > > Hi,
> >
> > I am working with the UART1 of the LPC2106 using the UARTecho
sample program with the KickStart board from IAR. The UART keeps
> generating the character time-out indicator interrupt. I have
looked through all of the documentation from Philips and I cannot
> find an explanation of what actually causes this interrupt. Does it
mean that a stop bit was not found in nine bit times from the
> start bit? Does it mean that the receive FIFO overran? Is this lack
of a clear and concise explanation indicative of Philips
> documentation? I am new to the LPC210x family, so please excuse my
lack of understanding if the answer is obvious. I have worked
> mostly with Motorola micros and there documentation seems more
concise.
> >
> > Thanks,
> > Bob Davis
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >