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Flasher STM8

Flash programmer for STM8 series of flash microcontrollers with on-chip flash



  • All STM8 devices can be programmed
  • Integrated optical isolation between host and target system
  • Standard 4-pin SWIM connector
  • USB 2.0 interface
  • Full duplex 100Mbit Ethernet interface
  • Target voltage can be measured & monitored during program
  • Fully plug and play compatible
  • USB, Ethernet, RS232 and 4-pin ribbon cable included
  • Windows PC software included
  • Free software updates1, 2 years of support
  • Target power supply via pin 1 of the 4-pin interface (up to 300mA to target with overload protection)
  • ASCII command interface to control Flasher without the use of PC program

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.

Package content

Flasher STM8 is delivered with the following components:
Flasher STM8 Ethernet cable 4-pin flat ribbon cable RS232 cable 1:1 female / male USB cable USB power supply


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
Electromagnetic compatibility (EMC) EN 55022, EN 55024
Operating temperature +5°C ... +60°C
Storage temperature -20°C ... +65 °C
Relative humidity (non-condensing) Max. 90% rH
Size (without cables) 121mm x 66mm x 30mm
Weight (without cables) 122g
USB interface USB 2.0
Ethernet interface 100Mbit, full duplex
RS232 Host interface RS232 9-pin
Target interface SWIM 4-pin connector
SWIM interface, Electrical
Power supply USB powered, 100mA for Flasher STM8. 500mA if target is powered by Flasher STM8.
Target interface voltage (VIF) 1.2V ... 5V
Target supply voltage 4.5V ... 5V (if powered with 5V on USB)
Target supply current Max. 300mA
LOW level input voltage (VIL) Max. 40% of VIF
HIGH level input voltage (VIH) Min. 60% of VIF

10-pin Needle Adapter

SEGGER offers the 10-pin Needle Adapter, which has been designed to connect Flasher 5, Flasher 5 PRO, Flasher ST7 or Flasher STM8 to a PCB which does not come with a mating connector or programming header. The designed pattern with 3 locating pins ensures that the adapter can only be connected in one way.

The 10-pin needle adapter allows manufacturers to save costs and space on their PCBs since there is no need to provide the PCB with additional connectors. It adapts from the 10-pin, 0.1 inch connector to a 10-pin, 0.05 inch needle pattern.


Download speed

Flasher STM8 has been designed to allow downloading to the target as fast as the target can receive and program flash. The table below shows the measured download speed for standalone programming and for programming via PC driven software. The following testing environment has been used:

  • PC with 2.53 GHz Core2Duo, running WinXP
  • USB 2.0 port
  • USB 2.0 hub
  • STM8S208MBT6B

Operation Standalone mode PC mode
Program (128KB) 8.5s (15KB/s) 8.5s (15KB/s)
Program and verify (128KB) 11.3s 11.3s