BreathUp: AES, PCB, and debug


During this end of the week, I worked on the AES and implement C and Python functions that encrypt and decrypt messages using AES128 CTR mode and they work pretty well.

I also worked on our PCB, and implemented some code to drive the LEDs with PWM.

We also discovered another problem: the quartzs are not oscillating, and as we need the 25MHz one for the USB, we still can’t use printf() to debug our drivers, witch makes thing a bit trickier. Therefore, while we are looking for a way to use the quartz, I worked on Segger Real Time Transfer (RTT) that should allow us to debug the code on the STM, but this is not working for the moment.

Eventually, during the beginning of the week I will work on RTT and on the quartzs.

Have a nice week,

Xavier Chapron

Makahiya – Wi-Fi module

Hi everybody,

As said in my previous post, I’ve worked on the Wi-Fi module. And it works very well. Using the module itself was much easier than expected. I just have to send commands to it on a serial connection to make it works. And it’s very easy to show a nice user interface to select the proper Wi-Fi network to connect to because it’s already provided by the OS embedded in the module.
I had more problems to configure the UART bus on the development board, even though it seems a very simple task. Most of the problems were quite stupid. For instance, on the Olimex E407 board, the pin number 8 on the Port D connector doesn’t correspond to GPIOD8 !! Because pins 1 and  2 are Vcc and GND. Once you discover it, you realize that you’ve spent the last hour working for nothing, really.
But now, everything works fine: I’m able to connect to my Wi-Fi network, to read web pages and to use the API of our server to update the database.

Now, I’ll continue to work with the Wi-Fi module and try to make it connect to the websockets Tanguy has created on our server.