Buffy is a debugging buffer library for embedded targets.

Buffy creates a circular buffer on the target side. Your code writes debug logs to this buffer, and it gets read from the PC side over a JTAG connection.

Buffy consists of two parts:

1. a small library that you link into your embedded code (this repo)
2. a python script that uses OpenOCD to exchange data with the code on the embedded side (see buffy-client)

You should be able to interact with the target using OpenOCD. It should have tcl_port enabled (default).

On the embedded side add embedded/buffy.c and embedded/buffy.h to your project using your favorite build system. Somewhere in your code include buffy.h and instantiate the debug buffer with INSTANTIATE_BUFFY(buffy);. Then_set up data to be sent to host with buffy_tx(&buffy, buf, len). You might want to create some sort of printf function that sprintfs into a buffer before calling buffy_tx.

See the buffy-client repo for the usage on the client side.

When you instantiate Buffy on the target, it creates two circular buffers, one for sending data from target to host, and one for reverse. The data structure also contains a magic word that the client can use to find the structure in memory.

Buffy uses OpenOCD's "RPC" interface to get data between the client and the embedded target. It could use some improvements.

This has been tested on 3+ Cortex ARM devices from different vendors. It should work on other platforms with minimal changes as long as your target has 32-bit wide debug access, and allows OpenOCD to read/write memory while the target is running.

Pull requests are welcome. Also, I would love if somebody cleaned up OpenOCDs RPC interface so it was less spammy and more reliable.

Stuff under external/ has their own licenses, everything else is BSD. See LICENSE.

Inspired by nekromant's stlinky and lk's cbuf.