J-Link OB

The J-Link OB (stands for: on-board) is essentially a microcontroller-based, single-chip J-Link that goes right on the evaluation board. It is compatible with and has the same features as the J-Link BASE with reduced, but still great, performance. It adds features such as debug support and download into Flash memory, without adding significant extra cost.

Customers can fully use, test, and debug the target device (typically a microcontroller) right out of the box. J-Link OB is compatible with most IDEs including Eclipse, GDB-based IDEs, and SEGGER Embedded Studio.

The microcontroller that is used as a J-Link OB (on the left side of the evaluation board in the diagram below) has a USB-interface on its left side (facing the host) and a JTAG/SWD + SWO interface on its right side (facing the target device).

Key features

Why use a J-Link OB?

J-Link OB turns an evaluation board into a complete evaluation kit!
It adds features such as debug support and download into Flash memory, without adding significant extra cost.
Customers can fully use, test, and debug the target device (typically a microcontroller) right out of the box.
J-Link OB is compatible with most IDEs including Eclipse, GDB-based IDEs, and SEGGER Embedded Studio.

Who uses a J-Link OB?

J-Link OB is used on various evaluation boards, by several evaluation board manufacturers, for numerous target devices.

Additional options

Drag & Drop Programming Option – Intuitive Programming of the Target Device

Drag-And-Drop is an optional J-Link OB intuitive programming feature. It allows programming of your target MCU in a very simple way.

J-Link OB with Drag-And-Drop capability appears both as a debug probe and as a flash drive on the user’s computer.
The high performance and functionality of flash download using a debugger and a J-Link still exists and is as straightforward as ever.
Drag and drop just makes it faster and even easier!
With the flash drive option it is now as simple as dragging and dropping a file (a Motorola S-record, an Intel Hex, or a plain binary) onto the J-Link drive. There is no need to install application software. Anyone that can drag and drop a file to a USB memory stick can now program the target on an evaluation board.

This J-Link Drive enables manufacturers, and third-party software developers, to deploy ready-to-go demonstration applications to customers who can then quickly evaluate the capability of the board, software, and device – all without installing software or drivers. All major operating systems (Windows, macOS, Linux) are supported.

Developed by SEGGER’s Embedded Experts Team, J-Link OB offers a compelling opportunity for board manufacturers to provide a highly polished way to deliver integrated solutions to customers, and enhance the experience over time by adding new applications and features that just “drop into place”.

Once customers are ready to do more than download fixed demonstration applications, they can unleash the full potential of the target board using the J-Link OB as a debug probe backed by unparalleled, industry-wide support.

Drag-And-Drop Flash Programming in Action

The image below demonstrates how easily the microcontroller on the SEGGER emPower (V2 Rev. D or later) can be programmed via the “Drag-And-Drop” option.

3. Relax and watch the demo which starts automatically after a few seconds, once programming is complete!

Please note that Drag-And-Drop is available upon request only.

Example implementations that support Drag-And-Drop flash programming: The following boards are already using J-Link OB implementations that support Drag-And-Drop flash programming:

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WebUSB programming option

WebUSB is an optional J-Link OB feature. It allows programming of the target MCU in a very easy way, using the web browser.

The high performance and functionality of flash download using a debugger and a J-Link still exists and is as straightforward as ever.

J-Link OB with WebUSB capability can also be accessed on the user’s computer via a web browser:

There is no need to install application software. Anyone that can use a browser can now program the target on an evaluation board.

Note: J-Link OB uses the WebUSB component SEGGER’s emUSB-Device.

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Virtual COM Port (VCOM) option:

Virtual COM port (VCOM) is a technology used to replace the traditional COM ports on modern PCs and laptops. From the host’s perspective, there is no difference between a physical (“real”) COM port and a virtual one.
Virtual COM port enables the J-Link OB to communicate with the host via a USB UART. Any terminal program can be used and this communication channel can also be used for other purposes.
For some J-Link OBs even multiple VCOMs are available.
VCOMs can be used in parallel with the J-Link functionality (so while debugging) or even when the J-Link is not in use (when no debug session is active).

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Debug Out option:

J-Link OB is designed to debug the target device. Using it to debug a device that is on another board, or to build debug probes (stand-alone J-Links), is not permitted under the standard license.
However, there is a debug out option, available for an additional charge, which allows using the J-Link OB to program and debug custom hardware.

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The PLUS Option:

A standard J-Link OB comes with the same options as J-Link BASE.
It does not allow the usage of unlimited breakpoints in flash memory, or the use of software packages such Ozone and J-Flash.
With the PLUS option, all of these software packages are also available to the end user of the J-Link OB.

Model overview / Supported cores

J-Link OB is essentially a microcontroller with a USB device interface running J-Link firmware. Below is a list of currently available options for J-Link-OB, along with the supported cores and interfaces.

Please note that not every J-Link-OB supports every core and every interface/feature. Other microcontrollers can be supported upon request.

J-Link OB model	OB Device	Supported target cores	JTAG	SWD	VCOM support	Drag & Drop support1	SWO speed	Interface speed	Download performance
J-Link-OB-K22-Cortex-M	NXP MK22FN128VLH10 LQFP64 package No external crystal required Cortex-M4 @ 96MHz, 128 KB flash	Cortex-M	Supported	Supported	Supported	Supported	4 MHz	4 MHz	200 KB/s
J-Link-OB-K22-Cortex-A		Cortex-A	Supported	Supported	Supported	Not Supported	4 MHz	4 MHz	200 KB/s
J-Link-OB-K22-RISCV		RISC-V (RV32, RV64)	Supported	Supported	Supported	Supported	4 MHz	4 MHz	200 KB/s
J-Link-OB-K22-Full		Cortex-M Cortex-A/R (ARMv7-A/R) Cortex-A/R (ARMv8-A/R) RISC-V (RV32, RV64)	Supported	Supported	Supported	Supported	4 MHz	4 MHz	200 KB/s
J-Link-OB-RA4M2-Cortex-M	Renesas R7FA4M2AB3CNE QFN48 package Cortex-M33 @ 96 MHz, 256 KB flash	Cortex-M	Supported	Supported	Supported	Supported	4 MHz	4 MHz	200 KB/s
J-Link-OB-RA4M2-RISCV		RISC-V (RV32, RV64)	Supported	Supported	Supported	Supported	4 MHz	4 MHz	200 KB/s
J-Link-OB-RA4M2-Full		Cortex-A Cortex-M Cortex-R RISC-V (RV32, RV64)	Supported	Supported	Supported	Supported	4 MHz	4 MHz	200 KB/s
J-Link-OB-STM32F072-Cortex-M-128KB	ST STM32F072CB UFQFPN48 package No external crystal required Cortex-M0+ @48 MHz, 128 KB flash	Cortex-M	Not Supported	Supported	Supported	Supported	250 kHz	2 MHz	100 KB/s
J-Link-OB-STM32F072-Cortex-M-64KB	ST STM32F072C8 UFQFPN48 package No external crystal required Cortex-M0+ @48 MHz, 64 KB flash	Cortex-M	Not Supported	Supported	Supported	Not Supported	250 kHz	2 MHz	100 KB/s
J-Link-OB-STM32F072-Cortex-A-64KB		Cortex-A	Supported	Supported	Supported	Not Supported	250 kHz	2 MHz	100 KB/s
J-Link-OB-STM32F103-Cortex-M	ST STM32F103TB VFQFPN36 package Cortex-M3 @72 MHz, 128 KB flash	Cortex-M	Supported	Supported	Not Supported	Not Supported	4.5 MHz	2.25 MHz
J-Link-OB-STM32F103-Cortex-A		Cortex-A	Supported	Supported	Not Supported	Not Supported	4.5 MHz	2.25 MHz	150 KB/s
Available, but not recommended for new designs
J-Link-OB-SAM3U128	Atmel ATSAM3U2C LQFP100 package Hi-Speed USB Cortex-M3 @96 MHz, 128 KB flash	Cortex-A Cortex-M Cortex-R	Supported	Supported	Supported	Supported	12.0 MHz	3.2 MHz	225 KB/s
J-Link-OB-SAM7S64	Atmel SAM7S64 LQFP64 package ARM7 @48 MHz, 64 KB flash	ARM7 ARM9 Cortex-A Cortex-M Cortex-R	Supported	Supported	Not Supported	Not Supported	6.0 MHz	12 MHz	700 KB/s

¹ Optional. Needs to be specified when ordering

Starter kits

J-Link OB Starter kits are available which allow eval board manufacturers to test the suitability of J-Link OBs on their specific eval board.
The following J-Link OB Starter kits are available:

StarterKit J-Link-OB-K22: The StarterKit J-Link-OB-K22 contains the following components:

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StarterKit J-Link-OB-STM32F072: The StarterKit J-Link-OB-STM32F072 contains the following components:

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StarterKit J-Link-OB-SAM3U: The StarterKit J-Link-OB-SAM3U contains the following components:

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StarterKit STM32F103: The StarterKit J-Link-OB-STM32F103 contains the following components:

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After evaluation of the J-Link OB, a production license needs to be purchased with information on the selected J-Link OB device. The following conditions apply for the usage of the J-Link OB technology: