pinetime-zephyr

Segger RTT (Real Time Transfer)

Serial data without a serial port

Pinetime does not have UART pins but UART-like connection can be achieved using RTT (Real Time Transfer) feature of Segger JLink debugger. RTT data can be accessed using the SEGGER tool (JLinkRTTViewer) or by using telnet connection to active debug session. Second method is recommended since it gives better throughput and allows bidirectional communication using Zephyr Shell (with RTT as backend). PuTTY can be used to telnet to debug session.

Prerequisites:

• JLink debugger, for example one of Nordic Semiconductor Development Kits.
• Setup: https://wiki.pine64.org/index.php/PineTime#Using_JLink_programmer_and_nrfjprog_tools

Following steps needs to be taken to run RTT shell in the application:

1. Install PuTTY and Setup RTT session. On Linux, copy misc/rtt_shell/rtt to ~/putty/sessions. On Windows, execute misc/rtt_shell/putty-rtt.reg.

2. Enable logging and shell over RTT: \ CONFIG_LOG=y CONFIG_USE_SEGGER_RTT=y CONFIG_SHELL=y CONFIG_SHELL_BACKEND_RTT=y ``

3. Build and flash application.

4. Start debug session \ west debug (will start gdb) continue (in gdb console) ``
5. Start PuTTY RTT session, prompt should be printed.

Resources:

• Zephyr shell documentation: https://docs.zephyrproject.org/latest/reference/shell/index.html
• Zephyr logger documentation: https://docs.zephyrproject.org/latest/reference/logging/index.html

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