reducing power of HRS sample

RE: reducing power of HRS sample

Simonr — Wed, 01 Mar 2023 08:40:05 GMT

Indeed, sounds like you figured it out. Yes, I did not remove the timers or buttons_leds_init() as I just measured the nRF52840 DK in "nRF Only" mode, so I wouldn't see the LEDs drawing current.

Best regards,

Simon

RE: reducing power of HRS sample

Johan.h — Tue, 28 Feb 2023 12:31:32 GMT

Well, I removed timers_init() and buttons_leds_init() from main.c, changed adv. time to 5 seconds. Now I am at less than 10uAmp. A good starting point to add functionality.

RE: reducing power of HRS sample

Johan.h — Tue, 28 Feb 2023 06:54:44 GMT

Hi, I tried your hex file as follows:

1. erased DK (PC10040) memory.

2. programed s132_nrf52_7.2.0_softdevice.hex and the hex file you made.

3. removed usb cable from DK.

4. power DK from PPk2 as in picture.

Average current is 385 uA, but an LED is blinking every 2 sec. which can explain this.

there is a 200ms pulse of about 2.5 mA with every advertisement.

Can you send me your main.c and sdk_config.h?

Johanan

RE: reducing power of HRS sample

Simonr — Fri, 24 Feb 2023 13:56:57 GMT

Here's the .hex file of the project, but it's literally just the ble_app_hrs example from SDK 17.1.0 with the APP_ADV_INTERVAL set to 3200 (2 seconds).

devzone.nordicsemi.com/.../5287.ble_5F00_app_5F00_hrs_5F00_pca10040_5F00_s132.hex

To measure on a DK I used the nRF52840 DK which has a switch to put it in "nRF Only" mode which lets you only power the nRF52 on it and not the debugger. That way you can get okay current consumption measurements when using DKs as well.

But the unknown spikes occurring every 2 seconds almost seem like the device is waking up the CPU (probably to do some calculations) now and again, but it's hard to know what wakes it up without seeing your project.

Best regards,

Simon

RE: reducing power of HRS sample

Johan.h — Fri, 24 Feb 2023 09:55:55 GMT

BTW, how can I measure actual current consumption with DK? I disconnect SB9 and use PPK2 on P22, but isn't the Jlink debugger always connected and draws current?

RE: reducing power of HRS sample

Johan.h — Fri, 24 Feb 2023 08:02:44 GMT

Thank you, this is good news which means I am missing something.

I started with the same project as you, it is on custom board which is very simple. MY IDE is visual Studio with VISUALGDB plugin, DK board as Jlink. I check current with Jlink not connected and after reset.

I will be happy to provide a link to the project or just upload main.c

On the other hand, can you send a link to your project, I will try to build it on my system and test.

Thanks for your support.

RE: reducing power of HRS sample

Simonr — Fri, 24 Feb 2023 07:39:34 GMT

What example project have you based your project on? I just built the ble_app_hrs example project on my end. I only changed the advertising interval to occur every 2 seconds, and I'm seeing an average current consumption of ~40µA on my end. Any chance you can upload your main file so we can take a look at what you're doing exactly. Also, are you testing on a Development Kit or a custom board?

(the spikes between advertisements are noise from the DK)

Best regards,

Simon

RE: reducing power of HRS sample

Johan.h — Thu, 23 Feb 2023 12:11:58 GMT

I am using SDK_15. I removed all the timers that I can see, by not calling application_timers_start(), set the adv interval to 5 seconds. Using PPK2, I can see the adv peak current every 5 seconds, but still see some activity every 2 seconds which I can't stop. Any idea what can it be? (Average current now about 450 uA).

RE: reducing power of HRS sample

Simonr — Thu, 23 Feb 2023 11:27:26 GMT

What SDK and SDK version are you using for development? How to get minimize current consumption depends on the SDK used. If you want to advertise as rarely as every 5 seconds, I think it shouldn't be a problem at all to go to sleep in between advertisement in order to save power. Same goes for between transmissions in a connection. You can use the Online Power Profiler for BLE to get some estimations on what you can expect at different advertising intervals, TX powers, etc.

Best regards,

Simon