RTT - integrate RTT as a debug output channel

[henrygab]

See https://forum.buspirate.com/t/feature-rtt-for-debug-output-was-3rd-com-port/651/10

• [ ] Integrate RTT foundation (header, etc.)
• [ ] Define at least one channel for generic (temporary) debug output.
  • [ ] Define a DEBUG_PRINT((channel, level, ...)) macro (or similar), which converts to a corresponding RTT call
  • Use of a macro (instead of directly encoding RTT calls in code) is intended to allow re-compiling to output at least the generic debug channel to a different channel, such as the terminal or additional CDC port, with smaller efforts.
• [ ] Define at least one other channel (of implementor's choosing) to highlight ability to have distinct output channels ... amaze us!

Resources:

• RTT Wiki
• RTT on GitHub

[henrygab]

Notes on host-side usage of RTT, using openOCD on linux based system:

Details

1. Run openOCD: `openocd -f interface/cmsis-dap.cfg -f target/rp2040.cfg -c "adapter speed 5000"` 2. Connect to telnet `telnet localhost 4444` 3. Send command to program `program ./build/src/bus_pirate5_rev10.elf` 4. Enable rtt server `rtt setup

` `rtt start` `rtt server start`

TODO:

• [ ] Integrate RTT into buspirate firmware
• [ ] Determine correct parameters for rtt setup
• [ ] View RTT channel 0 output (core 0)
• [ ] View RTT channel N output (core 1)
• [ ] View multiple RTT channels in a single terminal