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We’ve all been there. When debugging a microcontroller project, we just want to put in a print statement to figure out what’s going on with the microcontroller in real time. However, advanced embedded programmers know that printf statements are verboten: they’re just too SLOW. While not fixing this plight entirely, [Atakan Sarioglu] has come up with a clever way to create readable debug messages with minimal runtime overhead.

[Atakan Sarioglu]’s innovation, called BigBug (Github), is a dynamically-generated codebook. The codebook translates abbreviated messages sent over serial (UART here) to longer-form human-readable messages. To generate the codebook, BigBug automatically parses your comments to create a lookup between an abbreviation and the long-form message. When you are running your program on the microcontroller, BigBug will translate the short codes to long messages in real-time as you send log/debug data over serial.

For example (not restricted to Arduino-only), if you write Serial.println("HW") //@BB[HW] Hello World!, BigBug will translate the received characters HW\n to Hello World!. In this simple example, the abbreviation uses 3 characters while the fully readable message uses 13 characters, for a savings of ~75% with no loss of clarity. More advanced usage lets you log data: Serial.println("DT 1 1") //@BB[DT] Today's Date is: {0}/{1} becomes Today's Date is 1/1. You can also use enumerated variables (last example could showToday's Date is Jan. 1 with the same print command).

In terms of real-world benefit, using a 115200 baud connection (with 8N1 encoding) this is 115200 bits per second /(8+1) bits per byte = 12800 bytes/sec = 1 byte every 80 microseconds. Sending 13 bytes of Hello World!\n (in a naive, blocking UART implementation) takes ~1 ms of CPU time. With the shortcode HW\n, it would take ~0.25 ms to send essentially the same message (then decoded by BigBug). Note that because this just operates on serial data, BigBug is language independent

If you’ve been constrained by serial throughput for debugging, this looks like a well-polished tool to solve your problems. If you are just using an Arduino and throughput is no issue, then try this tool to debug Arduino programs. Or you could always double-down and use a microcontroller to debug another microcontroller.

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