What's Happening at SEGGER?

2021 |
Apr. 12
J-Link, Press Releases, Press Releases 2021
SEGGER J-Link Now Supports CMSIS-DAP: One Probe Fits All

SEGGER J-Link now supports CMSIS-DAP — One probe fits all

SEGGER's latest J-Link software makes it possible to turn J-Link into a high-speed CMSIS-DAP debug probe. 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,” says 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,” says 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.

About J-Link

SEGGER J-Links are the most widely used line of debug probes on the market. J-Link opens the door to all major development tools, from commercial toolchains to GDB driven ones.  With features such as Real Time Transfer (RTT) for interactive user I/O in embedded applications, and High Speed Sampling (HSS) for data acquisition, J-Link is a key component of third-party utilities that provide real time system tracing and inspection.

With J-Link comes J-Scope for Real Time Data Visualization and Ozone, the J-Link debugger. Also available is SEGGER Embedded Studio for generating and downloading programs using J-Link.

For more on J-Link, and for a full list of J-Link-related tools, please visit: