SWOViewer can be used without a debugger to capture terminal output independently from the debugger. Additionally, it can be run side by side with a debugger which does not support terminal output via SWO, such as GDB or GDB/Eclipse. SWOViewer is part of the latest J-Link software package which can be downloaded free of charge from SEGGER's website. It does not require a license and can be used on any current J-Link model.
“Many customers using GDB and Eclipse, have been asking us for such a tool in order to take advantage of this unique feature of the Cortex-M series CPUs. It also comes in handy when supervising a target outside of the control of the debugger. We believe it adds more value to the J-Link offering for anybody using a Cortex-M family CPU”, says Dirk Akemann, marketing manager of SEGGER.
SWO is a dedicated pin of ARM's Cortex-M debug interface. While it can be used to output various information in real time via the CPU, its main use is to handle terminal output in real-time with very low intrusion. This permits most programs to perform debug outputs via terminal without losing their real-time behavior.