Does IDD current measurement, includes the current passing through the RNG?

[VWolf.1]

Hello

I am doing a project where I investigate the increased energy consumption when implementing TLS on an MQTT protocol.

At the moment, I am doing tests where I measure the current via the IDD pins. But I was surprised at how little impact the implementation of TLS had. I am running with a specific Cipher suite DHE-RSA-AES128-GCM-SHA256. I did expect a longer working time where the MCU consumes more energy. But from what I can see in the pictures, it's just a small spike that always and only appears when I run with TLS.

So I wonder if it is so that Eg. RNG (random number generator) and other safety features power consumption does not go through the IDD pins.

I am using the STM32L476RG, connected via UART to an ESP8266 (Wifi-MCU). The pictures show the current in Cyan, and the blue line is the TX signal that I used to trigger on the oscilloscope.  

I would be incredibly grateful if anyone have the knowledge of this and can help me with the case.

Thanks in advance.

/ Victor

[waclawek.jan]

If you suspect any part of coffee code (autocorrect, sorry), just run it in a loop and measure current. You should be able to pinpoint the culprit using bisection.

JW

[Amel NASRI]

Hi @VWolf.1​ ,

If you would like to estimate the power consumption of your application, you need to refer to the datasheet and check the typical power consumption values per peripheral and depending on the power mode as well as frequency.

PCC (Power Consumption Calculator) tool embedded in STM32CubeMX will be of a great help on this regard to provide such estimation.

-Amel

[VWolf.1]

Thank you so much @Amel NASRI​ and @Community member​ , I'm new to the STM family and didn't think about it.

But I will definitely do so.

Thank you so much for taking your time to help, I really appreciate it.

Best regards

/Vw