8-bit MicrocontrollersのトピックRe: Real Low power

Real Low power

stevasway — Mon, 30 Oct 2006 22:45:45 GMT

Hi all,
I'm trying to develop an application using SMAC and low power features of MC13192 and
HCS08, but I have some problems, because my code hangs up.
I'm using RTI (1 sec) + Hibernate + STOP3 (_asm stop), and low power while for HCS08 _asm wait.

Does anyone have some suggestion, or example source code?

Does anyone have SMAC porting of PWRLIB for 802.15.4?, something else?

Thanks
Stevasway

Re: Real Low power

kbu — Tue, 31 Oct 2006 22:25:41 GMT

I've been able to get my circuit working fine with:

RTI(1sec) + MC13192Reset + STOP3 + MC13192 restart

except ofcourse the fact that while in STOP3 it still consumes 1mA of power!!!

Re: Real Low power

ok2ucx — Tue, 31 Oct 2006 23:08:17 GMT

Hi,

there's not enough details provided, but some further 'current-eaters' to look at:

BDM port enable/disabled? (SOPT1 > BKGDPE)

LVD circuit enabled/disabled? (SPMSC1)

STOP mode really enabled? (SOPT1 > STOPE)

In STOP3 you should be getting <1uA (typ. at 25 deg. C) by MCU, <3uA in Hibernate for MC1319x.

Not more.

Regards, Pavel ok2ucx

Re: Real Low power

stevasway — Wed, 01 Nov 2006 00:04:26 GMT

Hi ok2ucx,

BDM port enable/disabled? (SOPT1 > BKGDPE)

SOPT_BKGDPE = 0;

LVD circuit enabled/disabled? (SPMSC1)
STOP mode really enabled? (SOPT1 > STOPE)

SPMSC1 = 0; //Disable all LVD functions
SPMSC2 = SPMSC2 & ~0x03; // Enable deep sleep mode stop3 (PDC & PPDC =0)
SOPT_STOPE = 1; //Enable STOP mode(s)

is it all? IRQ PIN? SPI MISO ?

Thanks a lot!
Stevasway

Re: Real Low power

ok2ucx — Wed, 01 Nov 2006 00:26:09 GMT

just quick guess:

System Options Register 1 (SOPT1)

This high page register is a write-once register so only the first write after reset is honored.

of course any DC load or any other peripheral enabled in STOP mode might add some more current on top of mentioned ones.

Regards, Pavel

Real Low power & Watchdog

stevasway — Wed, 01 Nov 2006 00:44:07 GMT

Hi Pavel,
thank you for the annotation about SOPT write-once register.

One more question about low power: is it possible to use the watchdog or there no
way to use it?

Thank You
Stevasway

Real Low power & Watchdog & Clock sources Settings

stevasway — Wed, 01 Nov 2006 01:03:49 GMT

Uh, sorry
another question : I select a f_busclk = 1MHz with external 16MHz MC13192.

Which is, in your opinion, the better choice for ultra low power?

I saw in BeeKit PWRLib: 62.5KHz for the Radio and 16MHz for the MCU.

Thanks again
Stevasway

Re: Real Low power & Watchdog & Clock sources Settings

kbu — Wed, 01 Nov 2006 06:20:31 GMT

attached are two screenshots from a scope datalogger thats connected across a 10ohm shunt at VIN to my circuit. (i.e. 1 Y-div = 5 mA)

can someone please comment on the graphs and let me know if the profile you see there seem to match the annotations (and code)?

DEEPSLEEP MODE :

UseMcuClock(); // MCU internal clock selected since we'll lose our external clock

PWRLib_ClockSetup(SelfClk_2MHz);

SPMSC1 = cSPMSC1Init_LVD_Disable; // disable LVD

MC13192ContReset(); // Place the MC13192 into Reset mode

PWR_HandleDeepSleep(STOP3_MODE, 5);

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();

- Also why is there so much fluctuation in the consumption between 2 RTI IRQs?

Message Edited by kbu on 2006-10-3104:27 PM

Re: Real Low power & Watchdog & Clock sources Settings

bigmac — Wed, 01 Nov 2006 11:11:22 GMT

Hello kbu,

Looking at your Sleep Power Profile plot, it is suggestive that you have a superimposed hum component, although the frequency seems a little low for 50/60 Hz hum pickup. Is there anything in your code that cycles at about 16 Hz? I might suggest that you increase the resistor value to, say 100 ohms, and also place a schottky diode across the resistor to limit the voltage drop during transmit. Then see if the waveform still remains consistent with your current observations.

Can I assume that one side of the resistor is "grounded", and that you are not attempting a differential voltage measurement with the resistor in the positive supply lead?

The higher frequency "noise" component seems to indicate that there is still clock activity somewhere.

Regards,

Mac

Message Edited by bigmac on 2006-11-0101:19 PM

Re: Real Low power & Watchdog & Clock sources Settings

kbu — Wed, 01 Nov 2006 23:39:22 GMT

hi bigmac,

I am actually doing a differential measurement, with a resistor in series with V+.
does that mess up the results?

Re: Real Low power & Watchdog & Clock sources Settings

bigmac — Thu, 02 Nov 2006 12:04:46 GMT

Hello kbu,

For millivolt level signals, the differential measurement would mean that you would be more susceptable to pick up of extraraneous hum and noise during the measurement. This would be especially so if the common mode (power supply) noise was much greater than the signal you were attempting to measure, and the differential measurement was not precisely balanced.

I would suggest that you place the low value resistor in the negative side, and use a ground-referenced measurement, to see if the results are significantly different. Provided the voltage drop is small, hopefully the degredation of supply regulation won't affect the operation of the MCU too much. You may still need to connect a schottky diode across the resistor, to cater for the much larger transmit current.

Regards,

Mac

Re: Real Low power

stevasway — Thu, 02 Nov 2006 18:13:07 GMT

Hi all,
I'm glad to know that Low Power discussion is hot.

I have two questions regarding low power:

1 - Use of a watchdog in a low power code : is possible?
2 - SMAC & PWRLIB : does anyone knows anything?

Stevasway

Re: Real Low power

ok2ucx — Thu, 02 Nov 2006 20:45:37 GMT

Hi,

>1 - Use of a watchdog in a low power code : is possible?

In the S08GB family, the watchdog (COP) is driven out of BUCLK signal, thus in sleep mode, there's no clock available and no watchdog.

In contrary, S08QG family has an option of COP being driven out of internal ~1kHz oscillator (see chapter 5.4 of S08QG8 datasheet).

>2 - SMAC & PWRLIB : does anyone knows anything?

What do you need to know? SMAC are just simple drivers to handle MC1319x, MC1320x and MC1321x chip. Regarding the power saving features there are few functions to handle these. E.g. MLMEDozeRequest(), etc., all fully described in the reference manual.

Regards, Pavel

Re: Real Low power

stevasway — Thu, 02 Nov 2006 22:29:25 GMT

Hi Pavel,

1>
So if I go into STOP3 (SelfMcuClock) the watchdog is enabled or not? When I return from a STOP3 the watchdog is in the same previous state?

Using kbu previous example code:
while (1)
{
UseMcuClock(); // MCU internal clock selected since we'll lose our external clock

//----> now the watchdog test is not running, so I must not reset the watchdog

PWRLib_ClockSetup(SelfClk_2MHz);
SPMSC1 = cSPMSC1Init_LVD_Disable; // disable LVD
MC13192ContReset(); // Place the MC13192 into Reset mode
PWR_HandleDeepSleep(STOP3_MODE, 5);

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();
__RESET_WATCHDOG(); //Now the watchdog test is running
}

If I use :
LOW_POWER_WHILE() _asm wait?

2>
With 802.15.4 stack (BeeKit) is possible to include PWRLIB functions. They are very useful configurable libs, I thought that there was something of similar for SMAC stack, because I heard someone has already written something.

Re: Real Low power

kbu — Fri, 03 Nov 2006 23:07:10 GMT

hi stevasway,

I'm not 100% sure but I think you can't use COP while in the stop modes. I couldn't find anything explicit in the datasheets but the sample code in AN2493 they switch off COP before going into sleep.

BTW are you able to go into stop3 right now with the code you have? what current consumption are you seeing?

Re: Real Low power

kbu — Fri, 03 Nov 2006 23:49:53 GMT

BTW Pavel,
when you say we should be able to see 1.1uA in stop3, do you have your circuit configured with an external 32K xtal, or using the internal FLL?

Re: Real Low power

Alban — Sat, 04 Nov 2006 01:54:37 GMT

Hi,

1.1uA is far too low to be using a FLL.
Isn't STOP3 = full stop ? In this case, even the 32kHz XTAL is off.

Cheers,
Alban.

Re: Real Low power

kbu — Sat, 04 Nov 2006 10:30:32 GMT

Then any other idea why I might be getting this high consumption?

I'm definately in Stop3, all the things the app note asks I have turned off. The only thing I can't be sure of is if the Radio is still drawing more current.

one thing I'm a little confused about is how the RTI gets its clock source when its sleeping? the datasheet seems to suggest that the RTI has its own internal source (is this different than the low precision ICG??) if so when the stop code is actually called does the ICG and FLL completely stop working??

if its infact using the ICG's low precision clock, whats the lowest frequency I should be running at? Just before going into stop I manually set the system frequency down to ~50kHz.

Has anyone actually gotten the MC1321x with a 16Mhz crystal connected to the RF and no other external crystal, to go into this deep sleep mode and seen it draw less than 1 uA (heck I'll take 10uA if possible)

Re: Real Low power & Watchdog & Clock sources Settings

kbu — Sun, 05 Nov 2006 01:13:36 GMT

hi bigmac,
any chance for a rough diagram explaining the connection you were talking about?

Re: Real Low power

Alban — Sun, 05 Nov 2006 19:15:21 GMT

Hello Kbu,

Yes, RTI has 1kHz clock source (see Chapter 5.7 of datsheet S08GT60). Having a small dedicated RC oscillator helps achieveing very low consumption whilst still having a regular interrupt.

I wrongly assumed STOP3 was the deepest sleep as you wanted to achieve low power. But:

Stop modes: see Chapter 3.2 of datasheet S08GT60
– System clocks stopped; voltage regulator in standby
– Stop1 — Full power down of internal circuits for maximum power savings
– Stop2 — Partial power down of internal circuits, RAM contents retained
– Stop3 — All internal circuits powered for fast recovery

As with STOP3 everything stays powered-up, no wonder you get a high IDD.
Think about using STOP1 to get to very low consumption. It's a bit more work, but STOP3 is not really a STOP mode, but rather a WAIT...

Alban.