Target side implementation of the RTT (Real-Time Transfer) I/O protocol. RTT implements input and output via a debug probe using in-memory ring buffers and polling. This enables debug logging from the microcontroller with minimal delays and no blocking, making it usable even in real-time applications where e.g. semihosting delays cannot be tolerated.
While this crate is platform agnostic, some platform-specific code is needed for locking if you want to use the global rprintln! macro.
If using Cortex-M or RISC-V, there is built-in support with a feature flag:
# Cargo.toml
rtt-target = { version = "x.y.z", features = ["cortex-m"] }
# or
rtt-target = { version = "x.y.z", features = ["riscv"] }Otherwise, check the documentation for the set_print_channel_cs function.
Output directly to a channel object with write! or the binary write method does not require locking and therefore does not need any platform-specific code.
With a platform support feature, printing is as simple as:
use rtt_target::{rtt_init_print, rprintln};
fn main() {
rtt_init_print!();
loop {
rprintln!("Hello, world!");
}
}The examples-cortex-m and panic-test crates come with build files for the venerable STM32F103C8xx by default, but can be easily adapted for any chip as they contain only minimal platform-specific runtime code to get fn main to run.