BriscoeTech
commented
5 years ago Hello lfg6000,
Programming with a rtos definatley adds its own new sets of challenges and adds afew more moving cogs than people are used to have to think about when programming an Arduino. Sounds like you have an existing project and are merging it to use freertos? Without having seen your code (I would suggest posting it so we can take a look) I have afew possible things you can look into to help diagnose what is going on.
Based on the Malloc Failed blinking error code, I think I have afew things you can try out:
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Your project may have used up all the ram (heap) of the processor, look at the second rtos example project and try using the MemmoryFree function call in your non-rtos project's setup function to see if you are running close to using up all the ram. Making your project a rtos project could be putting you over the edge, especially if you are doing alot of string manipulation and haven't forced the strings to flash using the F() macro. For some reason, the MemmoryFree function does not work if put inside of a task, am still trying to figure that one out, try using it at the beginning and end of your setup function to see how much heap is being used up initializing everything.
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I have noticed that there are alot of classes out there (my experience neopixles, adafruit oled screens) that need to be declared as global variables outside of tasks so they work properly. By making them global, they get allocated onto the global heap and not on a rtos stack. Its not necessarily that they are not thread safe objects, but that there is some sort of assumption that the object has access to an Arduino dependency on the global heap. I think by putting them on a task stack, it causes it to not work properly.
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The malloc failure is triggered typically for me when you try and make a new rtos object and it cannot be made. The way the rtos is currently implemented is it does not allow dynamic allocation of rtos objects, they all need to be initialized in the setup function and before vTaskStartScheduler is called. Embedded systems don't do well with dynamic allocation since they can easily lead to heap fragmentation and crash the rtos, so that is why it is disabled. I would take a look and see if you are trying to do any dynamic allocation of tasks/semaphores/ques and make them allocated in the setup function before the rtos is started.
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Debugging the rtos can be hard, I agree lol. I would highly recommend starting with one of the blank examples and add one new piece of code at a time, and see if it causes a rtos crash. If you add too much at once, it will quickly become impossible to figure out what exactly about one line of code made it crash.
Hope that something in here is useful for you to diagnose what is happening. I recommend posting your code so we can take a look and see what is happening.
lfg6000
This is more of an observation than an issue. It would be good to get some feedback about these observations. I am probably missing something....
noticed that Arduino-FreeRTOS-SAMD21 would crash when using a 1.44" TFT Display from Adafruit along with it's corresponding libraries Adafruit_ST7735.h, Adafruit_GFX.h, Adafruit_SPITFT.h... The led would blink twice meaning: "2 blinks - Malloc Failed" I am guessing that the adafruit display libraries are not thread safe. Everything works fine if i run the same code w/o freertos.
noticed that Arduino-FreeRTOS-SAMD21 would crash when using ArduinoJson. Everything works fine if i run the same code w/o freertos.
i am using printf to debug, which is a bit painful when sorting crash issues. eventually i will hook up a PIO Unified Debugger w/ Black Magic Probe which will make sorting out the above issues much more doable and time efficient. Currently using the Visual Code with the PlatformIO plugin to write arduino code.