April-15-24
Starting the Implementation of OpenBlt Project
I am beginning work on implementing the OpenBLT project on a Nucleo 64 platform with an STM32-F446RE microcontroller.
In my previous job, I implemented this project for a STM34H53 platform. At that time, I didn’t have enough time to fully understand how the software works. I modified the sources to work with CAN bus for a demo, and then another task was assigned to me. However, I believe that OpenBLT has more potential, and I will need to use it for my projects in the future.
April-17-24
Read Documentation
I was reading the OpenBLT site and checking the download, Developer Blog, and wiki sections. I noticed that Nucleo-F446RE board have a demo with Modbus RTU, I didn’t know what it was, so I researched some information. Once I learned that Modbus RTU is a serial or Ethernet communication protocol based on master/slave architecture, I will try to set it up or modify it to flash applications with at least CAN. If I have time enough I’ll try to run another interface for example RS232 or USB.
Working with a custom OpenBLT
May-04-24
Recently, I have been studying the architecture of the OpenBLT project, and I noticed that it is simple to understand, although it has a good structure and is very complete in resource administration, such as CAN and RS232. The first steps to add features will be to enable the functions of USART to use a TTL converter to flash an application.
May-10-24
I publish in this blog how to import the project to STM32Cube IDE software, This is a tool provided by STM to use the protocol
May-14-24
The project is taking longer than I expected. I understand how the resources work, I configured the system, GPIOs, timers, and it still doesn’t work. Nevertheless, I am still trying. I am sure that the problem is a minor issue related to my own lack of knowledge.
May-17-24
Finally, I managed to enable RS232. I had some trouble with the connection because I accidentally defined ports twice. Also, I was trying to flash using the USB-TTL in a resource that is part of a virtual COM embedded with the STLink port. Oh well, now my focus is on setting up CAN.
May-20-24
While researching an example of CAN bus functionality for the Nucleo-F446RE, I found Controllerstech tuturial. It was so useful in helping me understand how to manage resources and enable CAN in my custom OpenBLT project.
I spent a lot of time on this challenge because the STM HAL CAN driver needed to be integrated into the project. My first obstacle was that CAN didn’t work. I wrote a test code to run only the configuration and transmission of a loop message to check if the baud rate was correctly enabled, but to my surprise, it did nothing. After a good amount of debugging time with ST-Link, I noticed that the functions HAL_CAN_Init() and HAL_CAN_Start didn’t work normally because a timer value was not updated by the HAL_GetTick() function.
Upon investigating why this happened, I found that HAL_GetTick() was defined in timer.h and also in stm32f4xx_hal.h. I solved this issue by renaming the function to HAL_GetTick_openblt in all files of the OpenBLT layer.
In Mexico, May 20 is the Psychologist Day, and my girlfriend is a psychologist. I forgot about it while dealing with the issue in the CAN bus. Sometimes I wish I weren’t so obsessive. If someday you read these lines, Honey, forgive me. I swear that I love you. But an engineer lost his ground debugging.
May-21-24
While taking snapshots for the documentation, I noticed that if the CAN interface is enable but not connected, the bootloader never starts. This is because, in the initialization routine, it needs to be connected to a CAN bus. If you encounter this issue and don’t want to connect a transceiver, you can cross the pins CAN_Tx and CAN_Rx to initialize the bootloader. This trick can help rule out software issues. I hope this saves you some time.
May-22-24
Challenge complete!
Finally the system is working and the documentation is done. If you come here loking for a solution, Enjoy it! You can see the process here: OpenBLT in Nucleo-F446RE.