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Log Levels and Interfacing

Very quickly, I want to touch on debugging. Crashes and unexpected behavior crops up a lot when working with something like this, and I don't think it would be prudent to not teach you how to debug your code.

Log Levels​

There are 6 different levels that a log can be set to

  1. None
  2. Error
  3. Warning
  4. Info
  5. Debug
  6. Trace

Each level supersedes the previous, meaning that at a warning log level, you will still recieve logs produced at the error level.

Printing logs​

To log errors and information at a specific level to our serial line, we are provided with 5 macros by furi's log.h header.

These are:

FURI_LOG_E(tag, format, ...) 
FURI_LOG_W(tag, format, ...) 
FURI_LOG_I(tag, format, ...) 
FURI_LOG_D(tag, format, ...) 
FURI_LOG_T(tag, format, ...)

The log level is denoted by the last character in the name. FURI_LOG_E being at Error, and so on.

Let's go through the parameters:

  • tag specifies a tag to identify your program by. Make sure this is identifiable, and not something that could be confused.
  • format specifies a cstring that will be the content of your message.
  • The variadic parameters that follow behave the same as printf might, giving your format string the data it might display.

A call to this macro might look something like this:

    FURI_LOG_I("BOX_MOVER", "x: %d, y:%d\n", x, y);