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Flasher Portable

Portable Flash Programmer for on-chip and external flash memory.

Flasher Portable is a programming tool for microcontrollers with on-chip and/or external flash memory. 
It has been designed to fill the need of an extremely portable, production grade flash programmer used for in-field firmware updates. 
No need to be tethered to an outlet, it is powered by standard batteries. 
Initial setup/preparation for stand-alone mode operation is done via the J-Flash software, also used by other Flasher models, which requires a PC running Microsoft Windows 2000, Windows XP, Windows 2003, Windows Vista, Windows 7, Windows 8 or Windows 10. 
Flasher portable also supports having multiple configurations/image files stored on the Flasher, so one unit can be used for different targets. 
Proper image selection is done by simply clicking a button. The currently selected image is indicated via LEDs. 
Adapters for all common connections are available which may be used to do everything from fully electrically isolating the Flasher Portable from the target device, to remapping the pins and reducing the pitch and/or pins to the target header. 


  • Stand-alone in-circuit-programmer (Once set up, Flasher can be controlled without the use of a PC program)
  • Powered by 3 standard AAA batteries (no external power supply required)
  • Supports having multiple configurations/data files being stored on Flasher
  • Push button allows easy selection between multiple images/configurations stored on Flasher
  • 128 MB internal memory for configuration and data file storage
  • Supports ARM, Cortex, PowerPC and Renesas RX cores. For a complete list, please click here
  • Supports internal and external flash devices
  • Free software updates1, 1 year of support
  • Data files can be updated via mass storage or via J-Flash
  • Target interface: JTAG / SWD / FINE / SPD
  • Programming speed typically between 30 KB/second and 1 MByte/second. Max. programming speed highly depends on target hardware and max. programming speed of the flash itself
  • Authorized Flashing allows to limit the number of flash programming cycles and to protect the Flasher against non-authorized access in case of external production

1As a legitimate owner of a SEGGER Flasher, you can always download the latest software free of charge. Though not planned and not likely, we reserve the right to change this policy. Note that older models may not be supported by newer versions of the software. Typically, we support older models with new software at least 3 years after end of life.
2Actual programming speed depends on flash & target hardware.

Documentation download       Subscribe to Flasher Portable software notification

Download software and documentation package (Flasher Portable uses the same software and documentation package as J-Link)


Package content

Flasher Portable is delivered with the following components:
Flasher Portable 20-pin, 0.1" target ribbon cable USB cable 3x AAA batteries

Available software

In order to set up Flasher Portable for stand-alone operation, you need the J-Flash software from the J-Link software and documentation package. The J-Link software and documentation package is available for download on our website: Software and documentation package download

Supported CPU cores / devices

Flasher Portable supports a wide range of cores/devices. For a complete list, please click here



Power Supply Can be powered via battery (3x AAA) or USB
USB Host Interface USB 2.0
Target Interface Standard 20-pin J-Link target connector (optional adapters available)
Serial Transfer Rate between Flasher Portable and Target Up to 15MHz
Supported Target Voltage 1.8V - 5V
Current drawn from target voltage sense pin (VTRef) < 25µA
Target supply voltage 4.5V max. (depends on current battery voltage)
Target supply current Max. 400mA
Operating Temperature + 5 °C ... + 60 °C
Storage Temperature - 20 °C ... + 65 °C
Relative Humidity (non-condensing) < 90% rH
Size (without cables) 130mm x 65mm x 25mm
Weight (without cables) 120g
Supported OS Microsoft Windows 2000
Microsoft Windows XP
Microsoft Windows XP x64
Microsoft Windows 2003
Microsoft Windows 2003 x64
Microsoft Windows Vista
Microsoft Windows Vista x64
Microsoft Windows 7
Microsoft Windows 7 x64
Microsoft Windows 8
Microsoft Windows 8 x64
Microsoft Windows 10
Microsoft Windows 10 x64

Target interfaces

Since Flasher Portable is compatible to J-Link it also supports the same target interfaces.
Currently the following target interfaces are supported:

  • JTAG
  • SWD
  • FINE
  • SPD

For more information about the target interfaces please refer to J-Link - Interface description.

Standard 20-pin connector pinout

Flasher Portable uses the standard J-Link 20-pin connector. There are various adapters available to fit all customer needs.

JTAG interface connector signals:

Pin Signal Type Description
1 VTref Input This is the target reference voltage. It is used to check if the target has power, to create the logic-level reference for the input comparators and to control the output logic levels to the target. It is normally fed from Vdd of the target board and must not have a series resistor.
2 Vsupply NC This pin is not connected in Flasher Portable. It is reserved for compatibility with other equipment. Connect to Vdd or leave open in target system.
3 nTRST Output JTAG Reset (optional). Output from Flasher Portable to the Reset signal of the target JTAG port. Typically connected to nTRST of the target CPU. This pin is normally pulled HIGH on the target to avoid unintentional resets when there is no connection. Not mandatory for Flasher operation. Should not be shortened with RESET. In case of doubt, leave open/unconnected.
5 TDI Output JTAG data input of target CPU.
It is recommended that this pin is pulled to a defined state on the target board.
Typically connected to TDI on target CPU.
7 TMS Output JTAG mode set input of target CPU.
This pin should be pulled up on the target.
Typically connected to TMS on target CPU.
9 TCK Output JTAG clock signal to target CPU.
It is recommended that this pin is pulled to a defined state on the target board.
Typically connected to TCK on target CPU.
11 RTCK Input Return test clock signal from the target.
Some targets must synchronize the JTAG inputs to internal clocks. To assist in meeting this requirement, you can use a returned, and retimed, TCK to dynamically control the TCK rate. Flasher Portable supports adaptive clocking, which waits for TCK changes to be echoed correctly before making further changes. Connect to RTCK if available, otherwise to GND.
13 TDO Input JTAG data output from target CPU.
Typically connected to TDO on target CPU.
15 RESET I/O Target CPU reset signal. Typically connected to the RESET pin of the target CPU, which is typically called "nRST", "nRESET" or "RESET".
17 DBGRQ NC This pin is not connected in Flasher Portable.
It is reserved for compatibility with other equipment to be used as a debug request signal to the target system.
Typically connected to DBGRQ if available, otherwise left open.
19 5V-Target supply Output This pin can be used to supply power to the target hardware. Supply voltage is 5V, max. current is 300mA. If not needed, leave open.

All pins marked NC are not connected inside Flasher Portable. Any signal can be applied here; Flasher Portable will simply ignore such a signal.
Pins 4, 6, 8, 10, 12, 14, 16, 18, 20 are GND pins connected to GND in Flasher Portable. They should also be connected to GND in the target system.
Power can be controlled via the J-Link commander. The following commands are available to control power:
Command Explanation
power on Switch target power on
power off Switch target power off
power on perm Set target power supply default to "on"
power off perm Set target power supply default to "off"