High Current Consumption in Secure DFU Bootloader for SDK 14.2

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

Simonr — Mon, 30 Sep 2019 13:30:01 GMT

What exactly is your application supposed/expected to do? If it starts up, then does a quick operation before going to sleep (system OFF) mode, which requires it to reset upon wake up, and does this frequently, that will cause the startup and the bootloader activation to trigger often, and might draw current. Please try to enable logging, and print a message upon reset to check if your application restarts frequently.

Best regards,

Simon

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

SK — Mon, 30 Sep 2019 06:38:30 GMT

Right now i am measuring average current using a power supply. If i run a standalone application without secure bootloader, it does not crash. Although application is not crashing w/ bootoader as well since i can see application is performing as expected. It's just the current consumption has gone high.

What would you suggest the reasons for application crashing with bootloader earlier?

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

Simonr — Fri, 27 Sep 2019 10:47:29 GMT

What might happen, is that your application crashes and constantly resets, which causes this excess current consumption as the bootloader is activated upon a restart. How are you measuring the current consumption? If you use the PPK for example, you should see the startup-spike over and over. You could also enable logging and call and print something at the start of your main loop, to check if the application is constantly resetting.

Best regards,

Simon

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

SK — Fri, 27 Sep 2019 08:30:21 GMT

Exactly! It is really high. This is when device is powered down. Switching off some peripherals as well in application to minimize the current.

By bond sharing, do you mean bond support? Yes, i am using that for buttonless DFU service.

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

Simonr — Fri, 27 Sep 2019 06:47:51 GMT

[quote user="Samarth"]If i use bootloader + application, current consumption is around 2.4 mA once i power the device down. [/quote]

And what is this number when the device is on? It seems way too high, and I don't think the bootloader alone is to blame. It must be causing something else to draw power as well (even though it shouldn't, as the bootloader and application are independent of one another).

As for your "silly question", this should be fine actually. As long as you don't use bond-sharing in your application, and use the same SoftDevice version for the bootloader and application, it should not be a problem using different SDK versions for the two.

Best regards,

Simon

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

SK — Fri, 27 Sep 2019 01:33:59 GMT

I have a silly question. Can i run secure bootloader on SDK 15.0.0 and application on SDK 14.2? Because migrating to a newer SDK for the whole application might take time i believe. Any suggestions?

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

SK — Fri, 27 Sep 2019 01:20:05 GMT

Hi,

If i just use bootloader, current consumption is around 2.3 mA.

If i just use application, current consumption is 30 uA once i power it down.

If i use bootloader + application, current consumption is around 2.4 mA once i power the device down.

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

Simonr — Tue, 24 Sep 2019 12:06:10 GMT

Do you see this current consumption when you're running the application or when the bootloader is running? There must be something keeping the CPU awake that causes this extra current consumption if you're running the application, as the bootloader shouldn't draw any excess current when it isn't active. Did you add any peripherals what so ever that might not be uninitialized properly?

In any case, I think it would be a good idea to migrate to the newer SDK, as the bootloader was not only optimized in current consumption but also in throughput in SDK 15.0.0. If you're interested, you can take a look at the migration guide here.

Best regards,

Simon

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

SK — Tue, 24 Sep 2019 08:59:52 GMT

Okay, that's good to know. Although, may i ask if you did any modifications on the bootloader code? settings maybe?

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

Toyman — Tue, 24 Sep 2019 08:56:50 GMT

OK. All I can say that I have a custom board with SDK 14.2 DFU and the the power consumption in sleep mode is around 10uA, so the bootloader itself is not a culprit in your case

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

SK — Tue, 24 Sep 2019 08:52:54 GMT

UART is disabled

RE: High Current Consumption in Secure DFU Bootloader for SDK 14.2

Toyman — Tue, 24 Sep 2019 08:44:39 GMT

make sure UART is still disabled