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+-- Forum: Tangara (https://forum.cooltech.zone/forumdisplay.php?fid=3)
+--- Forum: Firmware Development (https://forum.cooltech.zone/forumdisplay.php?fid=7)
+--- Thread: Forwarding JTAG over USB through SAMD21? (/showthread.php?tid=120)
Forwarding JTAG over USB through SAMD21? - Be - 2025-01-31
Is there any way to access the ESP32's JTAG interface over USB, or could there be with changes to the SAMD21 firmware? I was hoping to use probe.rs with my Tangara, but probe-rs doesn't detect it. I know the documentation says you can disassemble the Tangara and solder wires to the JTAG pins, but that's much more cumbersome than plugging in a USB cable. Is it still feasible to close the case if wires are soldered to the JTAG pins?
RE: Forwarding JTAG over USB through SAMD21? - Be - 2025-02-01
I figured out that I could log info over UART in Rust by using the "println" Cargo feature of esp-backtrace, using the "uart" and "log" Cargo features of esp-println, calling esp_println::logger::init_logger_from_env() at the beginning of main, and putting
[target.xtensa-esp32-none-elf]
runner = "espflash flash --monitor"
[env]
ESP_LOG="INFO"
in cargo/config.toml.
This isn't as pretty or performant as defmt over JTAG with probe-rs, but it works.