Hi every body,

I am working in application that use low power mode; to reduce the power consumption I would like to configure the I/O to be in High impedance state. Is there a way to do it?

Salman

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You need to think very carefully about pin states to
attain really low power sleep modes on a 430.

There is no "output, tri-state, Hi-Z" pin setting (at least
on the [124]xx families.)
If the pin is an output, it is either high or low.
If it is an input, it has a high impedance.
However, an input that is allowed to float may
toggle, which can consume enough current (remember
CMOS consumes most of its power during transitions)
to upset your low power consumption calculations.

The best practice is to design your system so you
can use pull-ups (internal or external) or configure
pins as outputs during low pwer modes.

On 07/11/2009, salmanksa wrote:
> Hi every body,
>
> I am working in application that use low power mode; to reduce the power
> consumption I would like to configure the I/O to be in High impedance state.
> Is there a way to do it?
>
> Salman
>
--
Andy
------------------------------------



(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )

--- In m...@yahoogroups.com, "salmanksa" wrote:
>
> Hi every body,
>
> I am working in application that use low power mode; to reduce the power consumption I would like to configure the I/O to be in High impedance state. Is there a way to do it?
>
> Salman
>
you can configure unconnected pins to be output, 1/0.

------------------------------------



(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )

Hi Salman,
> > I am working in application that use low power mode; to reduce
> > the power consumption I would like to configure the I/O to be in
> > High impedance state.
> > Is there a way to do it?

Your assumption sound coherent but your focus is wrong. If you want lower power consumption you've to check the datasheet for what to do with unused pins to achieve that.
For example, if I remember correctly, on the PIC16xx microcontrollers, unused I/Os were recommended to be left as inputs and tied to ground to reduce power consumption.

The MSP430 User's Guide states what to do with unused pins which not only includes I/Os, but JTAG pins, Vref pins, and other unused pins. For example see the MSP430x1xx User's Guide under chapter 2.5: "Connection of Unused Pins".

Regards,
Michael K.

--- In m...@yahoogroups.com, Andy Warner wrote:
>
> You need to think very carefully about pin states to
> attain really low power sleep modes on a 430.
>
> There is no "output, tri-state, Hi-Z" pin setting (at least
> on the [124]xx families.)
> If the pin is an output, it is either high or low.
> If it is an input, it has a high impedance.
> However, an input that is allowed to float may
> toggle, which can consume enough current (remember
> CMOS consumes most of its power during transitions)
> to upset your low power consumption calculations.
>
> The best practice is to design your system so you
> can use pull-ups (internal or external) or configure
> pins as outputs during low pwer modes.
>
> On 07/11/2009, salmanksa wrote:
> > Hi every body,
> >
> > I am working in application that use low power mode; to reduce the power
> > consumption I would like to configure the I/O to be in High impedance state.
> > Is there a way to do it?
> >
> > Salman
> >
> >
> >
> --
> Andy
>

------------------------------------



(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )