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Thread
2004-12-19 by nevelian
Hi,
I want to use P0.2 (SCL) & P0.3 (SDA) as GPIO, and are using the
following code;
PINSEL0 = 0x00000005;
PINSEL1 = 0;
IODIR = 0xFFFFFFFF;
IOSET = 0xFFFFFFFF;
According to the datasheet I should have setup P0.0 & P0.1 as Uart
pins and the rest as GPIO.
The UART works, as do GPIO P0.4 - P0.31, but why aren't P0.2 & P0.3
outputing high (or do they need pullups)?
Rob2004-12-19 by Robert Adsett
At 03:23 AM 12/19/04 +0000, you wrote:
>The UART works, as do GPIO P0.4 - P0.31, but why aren't P0.2 & P0.3
>outputing high (or do they need pullups)?
They do need pull-ups.
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, III2004-12-19 by Markus Meng
Hi, I2C normally needs pullup's regardless of the implementation ... Markus nevelian schrieb: > > Hi, > > I want to use P0.2 (SCL) & P0.3 (SDA) as GPIO, and are using the > following code; > > PINSEL0 = 0x00000005; > PINSEL1 = 0; > IODIR = 0xFFFFFFFF; > IOSET = 0xFFFFFFFF; > > According to the datasheet I should have setup P0.0 & P0.1 as Uart > pins and the rest as GPIO. > > The UART works, as do GPIO P0.4 - P0.31, but why aren't P0.2 & P0.3 > outputing high (or do they need pullups)? > > Rob > > > > > > > > Yahoo! Groups Links > > > > > > > > -- Mit freundlichen Gr\ufffdssen Markus Meng ************************************************************************ ** Meng Engineering Telefon 056 222 44 10 ** ** Markus Meng Natel 079 230 93 86 ** ** Bruggerstr. 21 Telefax 056 222 44 34 ** ** CH-5400 Baden Email markus.meng@... ** ** Web www.meng-engineering.ch ** ************************************************************************ ** You cannot create experience. You must undergo it. Albert Camus **
2004-12-19 by Leighton Rowe
How necessary is it for me to use pullups while implementing P0.3 as EINT1? Markus Meng <meng.engineering@...> wrote:Hi, I2C normally needs pullup's regardless of the implementation ... Markus nevelian schrieb: > > Hi, > > I want to use P0.2 (SCL) & P0.3 (SDA) as GPIO, and are using the > following code; > > PINSEL0 = 0x00000005; > PINSEL1 = 0; > IODIR = 0xFFFFFFFF; > IOSET = 0xFFFFFFFF; > > According to the datasheet I should have setup P0.0 & P0.1 as Uart > pins and the rest as GPIO. > > The UART works, as do GPIO P0.4 - P0.31, but why aren't P0.2 & P0.3 > outputing high (or do they need pullups)? > > Rob > > > > > > > > Yahoo! Groups Links > > > > > > > > -- Mit freundlichen Gr�ssen Markus Meng ************************************************************************ ** Meng Engineering Telefon 056 222 44 10 ** ** Markus Meng Natel 079 230 93 86 ** ** Bruggerstr. 21 Telefax 056 222 44 34 ** ** CH-5400 Baden Email markus.meng@... ** ** Web www.meng-engineering.ch ** ************************************************************************ ** You cannot create experience. You must undergo it. Albert Camus ** Yahoo! Groups SponsorADVERTISEMENT --------------------------------- Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/lpc2000/ To unsubscribe from this group, send an email to: lpc2000-unsubscribe@yahoogroups.com Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. --------------------------------- Do you Yahoo!? Yahoo! Mail - You care about security. So do we. [Non-text portions of this message have been removed]
2004-12-19 by Robert Adsett
At 06:41 AM 12/19/04 -0800, you wrote:
>How necessary is it for me to use pullups while implementing P0.3 as EINT1?
That would be as an input, yes? It that case it would depend on the drive
circuit producing your input. Certainly nothing else is going to
bring/hold it high.
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, III2004-12-19 by Markus Meng
I remember that I read somewhere, that you need a PU anyway, even if you do not use it for I2C. This implies that the output is always kind of 'open-drain'. For input only application it depends on the external driver. However adding a resistor that can be omitted if not necessary is not a 'big deal' ... Markus Leighton Rowe schrieb: > How necessary is it for me to use pullups while implementing P0.3 as EINT1? > > Markus Meng <meng.engineering@...> wrote:Hi, > > I2C normally needs pullup's regardless of the implementation ... > > Markus > > nevelian schrieb: > >>Hi, >> >>I want to use P0.2 (SCL) & P0.3 (SDA) as GPIO, and are using the >>following code; >> >> PINSEL0 = 0x00000005; >> PINSEL1 = 0; >> IODIR = 0xFFFFFFFF; >> IOSET = 0xFFFFFFFF; >> >>According to the datasheet I should have setup P0.0 & P0.1 as Uart >>pins and the rest as GPIO. >> >>The UART works, as do GPIO P0.4 - P0.31, but why aren't P0.2 & P0.3 >>outputing high (or do they need pullups)? >> >>Rob >> >> >> >> >> >> >> >>Yahoo! Groups Links >> >> >> >> >> >> >> >> > > -- Mit freundlichen Gr\ufffdssen Markus Meng ************************************************************************ ** Meng Engineering Telefon 056 222 44 10 ** ** Markus Meng Natel 079 230 93 86 ** ** Bruggerstr. 21 Telefax 056 222 44 34 ** ** CH-5400 Baden Email markus.meng@... ** ** Web www.meng-engineering.ch ** ************************************************************************ ** You cannot create experience. You must undergo it. Albert Camus **