diff options
| author | Ha Thach <[email protected]> | 2020-04-22 19:47:16 +0700 |
|---|---|---|
| committer | GitHub <[email protected]> | 2020-04-22 19:47:16 +0700 |
| commit | e2cd5159fd041240257eb2d200ccee09ce26d08c (patch) | |
| tree | fa89cf0f882a4dee6de2fc33ed40c5b61eead09e /examples/readme.md | |
| parent | 894a09f2ae7082fd9e850b76febed12dafecdcd4 (diff) | |
| parent | 5110ca712da34b1d826b31e5b0b336d927bca69c (diff) | |
Merge pull request #373 from hathach/add-log-swo
added swo as logger
Diffstat (limited to 'examples/readme.md')
| -rw-r--r-- | examples/readme.md | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/examples/readme.md b/examples/readme.md index 092787221..8d3d2e415 100644 --- a/examples/readme.md +++ b/examples/readme.md @@ -44,14 +44,22 @@ $ make LOG=2 BOARD=feather_nrf52840_express all ### Logger -By default log message is printed via on-board UART which is slow and take lots of CPU time comparing to USB speed. If your board support on-board/external JLink debugger, it would be more efficient to use it with [RTT protocol](https://www.segger.com/products/debug-probes/j-link/technology/about-real-time-transfer/) for logging. To do that add option `LOGGER=rtt` to build command e.g +By default log message is printed via on-board UART which is slow and take lots of CPU time comparing to USB speed. If your board support on-board/external debugger, it would be more efficient to use it for logging. There are 2 protocols: + +- `LOGGER=rtt`: use [Segger RTT protocol](https://www.segger.com/products/debug-probes/j-link/technology/about-real-time-transfer/) + - Cons: requires jlink as the debugger. + - Pros: work with most if not all MCUs + - Software viewer is JLink RTT Viewer/Client/Logger which is bundled with JLink driver package. +- `LOGGER=swo`: Use dedicated SWO pin of ARM Cortex SWD debug header. + - Cons: only work with ARM Cortex MCUs minus M0 + - Pros: even faster than RTT, and should be compatible with hardware and software debugger that support SWO. + - Software viewer is JLink SWO Viewer which is also bundled with JLink driver package. ``` $ make LOG=2 LOGGER=rtt BOARD=feather_nrf52840_express all +$ make LOG=2 LOGGER=swo BOARD=feather_nrf52840_express all ``` -The log can be retrieved by JLink RTT Viewer/Client/Logger software which is bundled with their JLink driver. - ## Flash `flash` target will use the default on-board debugger (jlink/cmsisdap/stlink/dfu) to flash the binary, please install those support software in advance. Some board use bootloader/DFU via serial which is required to pass to make command |