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Are the mBuino schematics available?


#1

If so where can I find a copy?

If not does anyone have any idea if there are any parts on the board that would draw about 120uA while the cpu is sleeping and if so if it would be possible to disable them?
Or it may be some pull up/down resistors in which case it may be possible to increase the values a little.

120uA doesn’t sound a lot but it’s 50 times the CPU power consumption in power down mode. That’s difference between lasting 6 months on a battery and lasting for the batteries shelf life.


#2

Is that 120uA in deep sleep mode? I thought I read a post somewhere a while ago from Gus or someone at GHI that confirmed the low current mode is just 0.5uA when in deep sleep mode. I have a good low current measurment setup at work. I will try to use it to do some measurement myself as well.


#3

Measuring power draw from the battery terminals I am seeing 480uA in deep-sleep mode and 120uA in Power-down mode. The LPC11u24 data sheet lists the power consumption in those modes as 360uA and 2uA respectively, a consistent ~120uA difference.

There is also a deep power down mode with a current draw measured in nA but that’s a lot more hassle to make use of both in terms of software and hardware requirements. 2uA in power down is low enough that things like battery self discharge rates start being a significant factor.

I am fairly certain everything in the CPU is getting shut down correctly and that I don’t have a bias in my measurement set up. I’d be happy to be proven wrong on either of those points.

The minimal code to get into deep sleep should be:


 #include "mbed.h"
int main () {
    LPC_PMU->PCON = 0x1;
    SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
    LPC_SYSCON->PDAWAKECFG &= 0xFFFFF800;
    __WFI();
}

For power down mode change PCON to 0x02;


#4

Wow, it is much higher than I expected. 480uA in deep-sleep mode and 120uA in Power-down mode for this small microcontroller is definetely not great for coin cell battery applications. One of our products at my day job uses a Freescale K70 processor which is very powerfull. But in low current mode that product uses only 50uA and then processor is still running and doing things and a fair deal of that current is from supporting electronic parts like regulators etc.


#5

We should be able to post this and any other needed details in the next few days. stay tuned for a huge announcement :slight_smile:


#6

hmmmm.

promises promises :slight_smile:

is this on mBed or NETMF ?


#7

We don’t want to ruin the surprise…lol


#8

G120 is gaining mBed support, is my guess.


#9

The thought entered my mind too but I was wondering if the 120 will be mounted on a base PCB with the HDK (or CMSIS) stuff on a supporting chip.

Maybe it will be like the mBuino, just drag and drop to the USB drive :slight_smile:


#10

And just how great and awesome would that be? :wink:


#11

I wonder how much more than the mbed NXP LPC1768. Will the extra memory and LCD be useful ? may the G120 will feature G sockets, I dont know if that will be good or bad…

:slight_smile: