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Power Budget of UsBizi 100


#1

I was hoping to run the UsBizi chip off a LiOn battery but I saw some (maybe) disapointing results . here is the code and some current figures…


        public void Main()
        {
            while ( true )
            {
                    LED58.Write( true );
                    Thread.Sleep( 10 * 1000 );

                    LED58.Write( false );
                    Thread.Sleep( 10 * 1000 );

                    // now go to hibernate - noone gets out alive
                   Power.Hibernate( Power.WakeUpInterrupt.BrownOutDetect );
            }

with the Led on we were drawing 70mA, with the Led off 60mA and in hibernate 2.8mA.
I was hoping that when the .NET is sleeping (ie no thread is running) then the current figures would be a lot lower, also the Hibernate mode isnt quite the 200uA as quoted.

Has anyone else had any experience in keeping these devices in a low power state so they can run off a LiOn battery


#2

I dont know if it will lower power levels but

Microsoft.spot.hardware.powerlevel can be low, med and high.

Do these setting change the current draw?


#3

Where are you measuring the current? Are you measuring the current to just the USBizi itself or to the board?


#4

measuring the board current…this is a board done by ourselves.
actually I have noticed the figures are simpilar to the ones given in the hardware comparison chart (duh)
I was hoping though that the idle state would be a lot lower, since a lot of the peripherals are off.


#5

In idle state, all interrupts and peripherals are still on. This way, you wouldn’t receive UART errors if a byte came your way and USB will still work…etc.

Hibernate will shutdown everything bringing the power in the under 1mA range but that is for the processor itself, not the whole board. We have measured everything for you on this page. http://www.tinyclr.com/compare/

Now, you are still not limited. We give you register access to the processor. This allows you to tweak the processor anyway you like to lower the power consumption as much as possible. Check the LPC23xx datasheet and user manual for deeper details please.