What kind of sample code is available?

Software called Simplicity Studio is provided as a development environment for EFM32PG /JG. In SimplicityStudio, in addition to the functions of a general integrated development environment (IDE) such as compiling, debugging, and programming, it also has a current consumption measurement tool (Energy Profiler), a peripheral setting tool (Configurator), product documentation, sample code, etc. Fully loaded with features and information.

There is a wealth of sample code available, ranging from flashing lights to Invader games (laughs).

• AES (project name: SLSTK3401A_aescrypt)
• ECDSA (project name: SLSTK3401A_ecdsa)

Reading the sample code readme file, it seems that the AES sample code uses AES and a SHA hash function. It seems that ECDSA (elliptic curve DSA) can be evaluated by switching between P-192, P-224 and P-256.

Starting with ECDSA...

Let's start by relying on the information in the readme file.
This sample code is coded using the API for ECDSA, but it is simple to count the time required for the processing and output the result from the virtual COM port.

Connect the starter kit (SLSTK3401A) to your PC and launch Simplicity Studio. SLSTK3401A is a common starter kit for Pearl Gecko and Jade Gecko, and the microcontroller is Pearl Gecko.

EFM32 Pearl Gecko Starter Kit SLSTK3401A

Now load the ECDSA sample code (SLSTK3401A_ecdsa), build it, and download the resulting binary to the EFM32PG, but before that, set the build setting to “Release”. If it is set to “Debug”, compression will not be applied during logic synthesis, so fair comparison cannot be performed.

In addition, you can select whether to enable or disable cryptographic hardware (CRYPTO) by setting parameters at build time. Disable the cryptographic hardware as follows:

Procedure: Select project -> Right click -> Property -> C/C++ Build -> Setting -> GNU ARM C Compiler -> Add "-DNO_CRYPTO_ACCELERATION" to Expert Setting

After setting, build and download.
In addition, if you look at the sample code main, it is set to use ECC P-256, so if you change this declaration, you can also use P-192 or P-224 for evaluation.

Settings on the PC side

The result (processing time) is sent via the virtual COM port, so you need to use terminal software to receive the data. I will use Tera Term this time. Select JLink CDC UART Port and set the communication settings to 115200-8-N-1 (baud rate 115200, data length 8bit, no parity, stop bit 1bit).

Result of software processing (Cortex-M4F, 40MHz operation, encryption hardware = disabled)

When you press the reset button on the starter kit, the sample code will run and the results will be displayed in TeraTerm.

Hardware processing result (Cortex-M4F, 40MHz operation, encryption hardware = enabled)

Now enable the encryption hardware and see the results as well.

Next time I would like to try the AES sample code.

• Finally equipped with a security engine! IoT era microcomputers have come so far! (4)

If you are interested in the EFM32 series microcontrollers, please also see here

• Let's use Silicon Labs' low power consumption microcontroller EFM32 using Macnica Online Service!

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