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

BreathUp: PCB, AES, LMIC and LoRa


As already explained by Benjamin and Alexandre, we received our PCB. Sadly, they contain some mistakes that will need to be patched and the LoRa part is quite compromised because of that… But anyway, we will do our best during the end of the week to patched them and you will be able to find an update in next Sunday’s post.

I also worked with Alexandre to set up our ChibiOs project, including: configuring the board, the clocks, creating a basic test program…

Eventually, I worked on LMIC and AES. I concluded that we cannot use LMIC’s AES function for the Bluetooth communications and we will therefore create an other one.

For the end of the week I want to work on the patch of the PCB, the basic development on the PCB (LEDs, PWM, UART, shell…) and on LMIC implementation on RFM95W chip that we might use in our PCB patch.

Have a nice end of the week,

Xavier Chapron