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The Keil ULINKpro USB-JTAG/SW Debug and Trace Unit connects the PC's USB port to the target system's connector via JTAG or Serial Wire, and allows users to:

  • Download and test programs on target hardware.
  • Capture and analyze trace information.
  • Program the FLASH memory of many devices.
  • Use JTAG or Serial Wire signals.
  • Define unlimited breakpoints in RAM.
  • Debug on multi-core devices based on Cortex-M microcontrollers.

ULINKpro supports the CoreSight Technology.



  • For ARM7 and ARM9 processor-based devices, two hardware breakpoints are supported in Flash memory.
  • For Cortex-M processor-based devices, six hardware breakpoints are supported in Flash memory.

Technical Characteristics

Parameter Description
Supply Voltage Provided through the PC's USB bus
Operating Voltage1 3.3V. Pins are 5.0V tolerant
I/O Voltage Range 1.2V .. 3.3V (see notes)
USB Interface USB 2.0
Supported Core Clock Up to 200 MHz on Cortex-M processors (selected devices may have trace-port bandwidth limitations).
JTAG/SW Clock Speed ≤ 50MHz
SWO Trace Capturing Frequency range: 3kHz..200MHz
Data rate range: 1.5kbit/s..100Mbit/s (Manchester Mode)
ETM Trace Capturing Frequency range: 0..100MHz Double Data Rate (DDR)
4-bit Trace Port data rate: 800 Mbit/s (600 Mbits/s with 5V Adapter)

Refer to Technical Specifications and Hardware Description for further characteristics.

ULINKpro Adapter


  • ULINKpro operates at 3.3V. All JTAG pins are 5V tolerant, which means that 5V can be applied to the inputs without damaging them and that 5V will be recognized as logic high. However, when ULINKpro generates a logic high, the voltage will take a value between 1.2V and 3.3V.
  • For target devices that require the generation of 5V logic levels, add the ULINKpro 5V adapter to your ULINKpro in place of the 20-pin cable.
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