In this mode, it can be used with any toolchain or application that is compatible with this standard, such as pyOCD, KEIL MDK and Arm Development Studio.
This mode is available for J-Link BASE, J-Link PLUS, J-Link EDU, J-Link ULTRA+ and J-Link PRO. These intelligent debug probes use a 480 Mbps high-speed USB connection to eliminate idle periods and drive the target interface at its full speed, up to 50 MHz on J-Link ULTRA+ and PRO.
"In addition to its own API and the standard GDB protocol, J-Link now supports CMSIS-DAP operation, a simple, low-level USB protocol for debug probes,” said Rolf Segger, founder of SEGGER. “While CMSIS-DAP doesn’t deliver the same performance as the J-Link protocol, it is widely supported. We decided to add support for it to make J-Link even more universal. J-Link is now the fastest CMSIS-DAP debug probe that we are aware of. One probe fits all.”
“All SEGGER products flow from the same philosophy of high-quality, reliability, speed, ease-of-use and universality,” explained Ivo Geilenbrügge, Managing Director at SEGGER. “Combining J-Link with a 3rd-party or open-source program that uses CMSIS-DAP is now as simple as plug-and-play.”
Switching to CMSIS-DAP mode and back to J-Link is easily done via J-Link Configurator. While J-Link gets the most out of CMSIS-DAP, J-Link’s full performance, functionality and feature set require J-Link mode.