8-bit Microcontrollers中的主题 Re: Lowest Power Consumption

Lowest Power Consumption

kbu — Tue, 11 Apr 2006 02:08:26 GMT

HI,
I have a GT60 and MC13192 on a module. I've been able to get the micro to get into Stop2 with a 1sec RTI, I'm having trouble getting it to consume close to the power consumption listed in the datasheets.

Here's the setup :
The MCU is set to 2Mhz internal clock.
Radio is reset.
1.024 sec RTI initialized. (10 second wake up times before doing a transmit on the radio)
all i/o pins on all ports set to 0x00.
LVD disabled.
MCU enters Stop2 mode.

According to AN2493 (GT60 Low power modes), while in stop2 with RTI enabled the system should draw close to 890nA.
However with my setup, the board seems to be drawing around .4 mA (fluctuates between .428mA and .438mA) . There are no other components on the board, and I'm guessing even with other quiescent current losses I should get a number closer to whats stated in the datasheet.

Has anyone gotten close to this number with their circuits. Any advice?
Thanks.

Re: Lowest Power Consumption

alex_spotw — Tue, 11 Apr 2006 02:12:19 GMT

HI:

What are you using to measure the current? It the instrument precise enough to give a close measurement to nA?

Waht else do you have in your hardware that might be consuming power? (external memory, devices, the power supply, etc?

Let us know!

Regards,

Alex

Re: Lowest Power Consumption

kbu — Tue, 11 Apr 2006 02:18:48 GMT

I'm using a scope to measure between the legs of a 100 ohm in series with the power supply.

No other devices, this is a zigbee module so only those two components.

Re: Lowest Power Consumption

bigmac — Tue, 11 Apr 2006 09:49:05 GMT

Hello kbu,

The current you are measuring seems to be roughly that for idle mode of the MC13192, rather than one of the other lower power modes (with SPI inactive). Is this a possibility?

Any floating unused inputs on the MCU without pullups enabled? Any unused inputs on the MCU shorted to ground, and with pullups enabled?

Regards,
Mac

Message Edited by bigmac on 04-11-200612:55 PM

Re: Lowest Power Consumption

yb — Tue, 11 Apr 2006 14:49:49 GMT

Hi,

Perhaps you measure your current BEFORE the power regulator, and your current is its consumption...

Re: Lowest Power Consumption

kbu — Tue, 11 Apr 2006 23:10:12 GMT

Mac:
You're right, I'm not sure which stop mode the micro is going into..
I tried putting the micro to stop1 but I can tell from seeing the current usage that its not going there, because the RTI is still running. Similarly I'm not sure if infact its going into Stop2 when I ask it to go there.

Many floating pins on the board, a few connected to leds and buttons.. I've done a pullupenable on all of pins (irrespective) and set their data direction to in and set their states to low. But I get the same current profile.

So I guess the question is, how can I tell which stop mode the mcu went into for real.

yb:
the circuit doesn't have a regulator, just a direct 3.3V battery or power supply source.

Re: Lowest Power Consumption

paul — Wed, 12 Apr 2006 04:05:24 GMT

Do you have the PDC and PPDC bits set to 1 in the "System Power Management Status & Ctrl Reg 2" (SPMSC2 bits 0:1)? These need to be set for STOP2 mode.

Re: Lowest Power Consumption

kbu — Wed, 12 Apr 2006 20:28:28 GMT

Yep those bits are set.

Re: Lowest Power Consumption

rao — Fri, 21 Apr 2006 19:16:00 GMT

Hai,

I am using stop3 and RAdio off .but i am facing problems regarding EXIT from it.

Can u help me please.

Re: Lowest Power Consumption

kbu — Wed, 25 Oct 2006 04:40:34 GMT

I finally got back to this problem. I just cannot get my MC13213 to get into low power consumption STOP2 mode.
the lowest power it seems to consume is around 900uA.

My most of the IO pins on the board are floating (but I've set them all to outputs), its a direct feed from a 3.3V battery. nothing else on the board except for the TX/RX circuit (LC/baluns etc)
I'm using SMAC4.2 and have incorporated some of the functions from PWRLib into it.

my code is basically this :

case DEEP_SLEEP_STATE:

UseMcuClock(); // switch to the internal clock
//Observations: I see clock speed drop to ~4Mhz in the debugger

// set clockspeed to 2Mhz
PWRLib_ICG_Divider_Setup( N8, R2); //ICGC2 = ((07) | (N4) | (03) | (R0));
PWRLib_ICG_Mode( LOW_CLOCK); //ICGC1 = ((Clock6) | (05) | (Mode3) | (02));
//Observations: I see clock speed drop to ~2Mhz in the debugger

SRTISC=0x00; //Disable wake up timer.
SPMSC1=0x00; // disable LVD
SPMSC2=0x00; // set PPDF flag to 0

MC13192ContReset(); // Place the MC13192 into Reset mode
//POTENTIAL PROBLEM: the SMAC function seems to set IRQPE = 0 (AN2493 seems to suggest setting it to 1)

// set IRQPE to 1
IRQSC = 0x1E;

//set all IO pins to outputs
(e.g. #define mPWRLib_SETUP_PORT_{ALL} PTADD = 0x00;\
PTAPE = 0x00;\
PTADD = 0xff; )

PWRLib_SetMCUIOForPowerSavingMode();

PWRLib_RTIClockStart( cPWR_RTITickTime, DozeDuration);
while ( PWRLib_RTIClockCheck() > 0)
{
SPMSC2 |= 0x03; // Sets PDC and PPDC bits for Stop2 mode
__asm STOP;
//OBSERVATIONS: Current consumption is around 900uA.
}
PWRLib_RTIClockStop();

RadioInit();
AppInit();

// Restart to external clock appx. 10.8mS
MC13192Restart(); // Bring the MC13192 into the desired Idle condition.
MC13192Init();

MLMESetChannelRequest(2);
MLMESetMC13192ClockRate(0); // Set initial Clk speed
UseExternalClock(); // switch clock sources from mcu to MC1319x CLKO

gi8AppStatus = TRANSMIT_DATA;

break;

Any idea whats going on?