51802 debug mode consuming less power?

RE: 51802 debug mode consuming less power?

Sigurd — Fri, 15 Sep 2017 14:48:41 GMT

Hi Borden,

I have now tested on a 51802, but it act the same as the 51822. The 51802 uses abit more current overall than the 51822, but the 51802 also uses more current in debug mode than in normal mode for me. Actaully for me it uses 1.6 mA more in debug mode.

Are you sure that the chip is actually working when you have it debug mode? is the debug mode interfering with any other components on your board? Are you using a original/legal(non-copy) debugger?

You could also ask for a design review in mypage. Remember to upload all schematics and geber files.

RE: 51802 debug mode consuming less power?

Borden — Thu, 07 Sep 2017 09:30:50 GMT

I haven't test it on a 3V config or other than 51802 because this board is currently is the only one I'm working on.

The LED pin output low when LED should be on, or disconnected when LED should be off. The button pin is a internally pull-up inpiut, a button simply connect to GND and this pin will work.

Maybe 51802 act differently from 51822? or maybe the debug module act differently under external 1.8V?

RE: 51802 debug mode consuming less power?

Sigurd — Wed, 06 Sep 2017 12:49:27 GMT

I tested using a 51822/51422. How should the P26 and P09 be connected ?

Have you tried removing the DC-DC, and running your 51802 at 3V ?

RE: 51802 debug mode consuming less power?

Borden — Mon, 04 Sep 2017 13:19:39 GMT

Yes I've connected DEC2 to 1.8V, I've checked just now. Were you testing my firmware on 51822 or 51802? Your readings looks far from mine. I've connected the power LED to P26(pin 45), and the power button to P09(pin 15), which I've forgotten to tell you, sorry. You may check it again with this LED and button, if it's not too bother for you.

RE: 51802 debug mode consuming less power?

Sigurd — Mon, 04 Sep 2017 11:22:06 GMT

Hi,

I have now tested the hex you uploaded on a nRF51-DK.

I measure 1.56 mA in regular mode, and 2.3mA in debug mode. After 30 seconds I get a Advertising timeout event, and the current goes up to 4.6 mA. This could be an issue with entering system OFF mode.

Could it be that you are measuring the current from other components on your board? Have you tried testing with 3 Volt?

Note that since you are running the chip in low voltage mode(under 2 Volt), DEC2 shall be connected to VDD. Have you done this on your custom board?

RE: 51802 debug mode consuming less power?

Borden — Mon, 28 Aug 2017 08:09:24 GMT

nrf51422_xxac.hex

Hi Sigurd, here's the hex file for you to test, it works with S130v2.0.1, thanks!

RE: 51802 debug mode consuming less power?

Borden — Mon, 21 Aug 2017 12:20:01 GMT

ok, I will upload files later. And I've tried wfe/sev/wfe combo, no difference.

RE: 51802 debug mode consuming less power?

Sigurd — Mon, 21 Aug 2017 10:42:09 GMT

You can upload the hex in the answer(or google drive, dropbox,etc ). You can also try to use

__WFE();
__SEV();
__WFE();

instead of the single __WFE();, and see if that makes any difference. Aslo, have you had your board-design in for layout review?

RE: 51802 debug mode consuming less power?

Borden — Sat, 19 Aug 2017 03:18:19 GMT

Yes I've been guessing the same thing, that's why I asked this question at the first place, to check if there's any peripheral should have been stopped but I didn't. But today I've found some more interesting things, I tested my board in BLE mode, the same result. When steadily connected:

debug mode on: 3.11mA;
debug mode off: 2.33mA;
normal mode on: 4.16mA;
normal mode off: 0.02mA.

These two radio mode share the same key scan code, but currently there's nothing I found suspicious. my 2.4G code is very simple, only two int handler, Timer0 and Radio, nothing else, and the main loop look like this:

	// Enter main loop.
for (;;)
{
	__WFE();
}

If any int handler miss, the connection can't be held steady. When in debug mode, the board function normally, and the 16M clock is no change, I've checked this with oscilloscope. Anyway, without my usb dongle, you can't test it in 2.4G mode, but you can test in BLE mode, so how should I send the hex file?

RE: 51802 debug mode consuming less power?

Sigurd — Fri, 18 Aug 2017 14:15:22 GMT

I have not seen this issue before. The results you are seeing could indicate that debug-mode is making something stop in your code, or change the way your code run in some way. Debug-mode itself will not use less power, but could trigger something else in your code to use less power. (e.g. debugmode makes you miss a interrupt that should have started something in your code, etc). If you could provide the .hex file, I can test it here.

RE: 51802 debug mode consuming less power?

Borden — Thu, 17 Aug 2017 03:48:18 GMT

I've uploaded a better video to make things more clear:video 2

In this one I turned on an LED to indicate syetem is on or off. now we can see:

In the first stage, when I powered it on, it's 3.86mA. then I turned it into system off mode, we read 0.02mA, so clearly the chip is in the normal mode.
then I triggered it into debug mode, we got about 2.80mA, after I turned it off, it read 2.32mA, that showed the chip is in debug mode.

I think this clip can make things obvious, that when my board is in debug mode, the power consumption is less than normal mode, over 1 mA, I can't understand that, I hope I can get some help here, 1mA lower power is a big temptation for me which I don't want to miss.

RE: 51802 debug mode consuming less power?

Borden — Wed, 16 Aug 2017 11:42:02 GMT

I've already had a pull down resistor on SWDCLK pin. It's unlikely that my board entered debug mode at the first place. As you can see, after I triggered my board into debug mode using jlink, I long pushed a button on the back of the board to turn it off, then we read a 2.32mA in system off mode, that can prove the board is in debug mode. Then I pushed the button again to turn the board on, it's still 0.88mA, I believe that's the power consumption of the debug mode.

RE: 51802 debug mode consuming less power?

Sigurd — Wed, 16 Aug 2017 11:16:54 GMT

It could be that the chip enters debug mode when you first power the board on, even if the debugger is not connected. It won’t enter debug mode just by simply plugging in the debugger, but since the board does a power-on reset when you connect the debugger, it could actually exit debug mode when you connect the debugger and go into normal mode. After you remove the debugger, it would continue to stay in normal mode.

What does the on-board button do?

If you start a debug session in KEIL, and let the program run, what current do you measure then?

From the reference manual, we have that

To guarantee that the device remains in normal mode, the SWDCLK line must be held low, that is, '0', at all times. Failing to do so may result in the DIF(Debugger Interface) entering into an unknown state and may lead to undesirable behavior and power consumption.

Could to try to connect the SWDCLK pin to ground, and then start your board up, and see what current you measure then.

If the issue is still present after this, you should check for floating pins that could be causing this.

RE: 51802 debug mode consuming less power?

Borden — Wed, 16 Aug 2017 08:13:41 GMT

Here's a shabby video I've made just now: video

My board have only a 3V power, and a multimeter attached to a 10ohm power line series resistor.

When I turn the power on, we can read a steady 1.99mA after power on initialization(a little lower than yesterday's 2.21mA for some unknown reason).
then I have a jlink attached, we can see the board reset, after an initialization, we get a steady 0.88mA.
then I remove the jlink, it still stay at 0.88mA.
When I use a on board button to turn the board off, we read 2.32mA, which further prove the board is in debug mode. If I turn my board off in normal mode, I read 0.02~0.03mA.
I turn my board on again, it still read 0.88mA.
then I turn the power off and on again, my board recover to 1.99mA of the normal mode.

RE: 51802 debug mode consuming less power?

Borden — Tue, 15 Aug 2017 14:38:26 GMT

Yes I've had the same thought, so I've experimented, it's not leakage. Once the chip is in debug mode, it stays at 0.96mA, even after I pull the jlink off, until another power cycle.

And for the gpio polling, thanks for your advice, I know it's not efficient, but I'd like to optimize that after this problem made clear, step by step. The main reason that I haven't use the GPIOTE is it can't detect both edge at the same time, and my number of buttons is more than 4, make the GPIOTE inapplicable in my case, not even the extra power it needs, since my 16M clock is always running, I don't think it will draw more power.

RE: 51802 debug mode consuming less power?

Sigurd — Tue, 15 Aug 2017 14:17:41 GMT

Ok, then I suspect that this is leakage current, i.e. you are getting current from the debugger into the nRF51-chip, and therefore partly powering the chip from the debugger. You are therefore measuring a lower current when the debugger is connected.

The cpu is running the main loop steadily merely check for GPIO buttons

Note that this is not power-efficient at all. In order to reduce the current here, you should instead set-up a interrupt for the GPIO buttons, so that the CPU can stay in sleep mode. Take a look at e.g. the pin_change_int example in the SDK.

RE: 51802 debug mode consuming less power?

Borden — Tue, 15 Aug 2017 13:27:15 GMT

Yes I have this resistor on the SWDCLK pin, but that makes no difference, with or without it, I got the same result. When I paused my program in keil, I measured about 0.7xmA, 0.96mA is when my program running. As I mentioned above, this current is read before my DC-DC, which I feed with 3V, so it's about 0.96 / 1.8 * 3 * 0.9 = 1.44mA drawing by 51802, which is much lower(over 50%) than my board running with no jlink attached.

RE: 51802 debug mode consuming less power?

Sigurd — Tue, 15 Aug 2017 12:35:38 GMT

If I power on the board with jlink plugged, then enter the debug mode with the keil debug settings panel, I got the same result.

You are measuring 0.96mA when debugging in KEIL ?

Note that we recommend to add a small resistor(1k ohm) on the SWDCLK line to make it more robust for unexpectedly entering debug mode. Do you have this resistor on your custom board ?

RE: 51802 debug mode consuming less power?

Borden — Tue, 15 Aug 2017 08:15:29 GMT

Yes the actual operation is a little different from what I described in my question.

Actually when there's no jlink plugged, I power on the board, I get 2.21mA; then I plug the jlink in with the board still powered, then I get 0.96mA instantly.

If I power on the board with jlink plugged, then enter the debug mode with the keil debug settings panel, I got the same result. So what I'm trying to say is I think I can tell the running state of the chip properly, hope you can help me more Sigurd, thanks!

RE: 51802 debug mode consuming less power?

Sigurd — Tue, 15 Aug 2017 07:51:45 GMT

When you did the reset on your board, you exited debug mode (even if the Jlink was plugged in).

RE: 51802 debug mode consuming less power?

Borden — Tue, 15 Aug 2017 07:29:04 GMT

Yes this is what I expected too, but what I saw is contrary, debug mode consuming less power, and much less, that's what confused me, and make me wonder if I should make the chip always running under debug mode...

RE: 51802 debug mode consuming less power?

Sigurd — Tue, 15 Aug 2017 07:19:16 GMT

Hi,

It’s actually the other way around. When you do a power-reset, the nRF51 will exit debug mode. Debug mode consumes around ~1mA, so you will see a ~1mA reduction when you resume normal mode. Please see section 11.1.3 "Resuming Normal Mode" in the nRF51 reference manual