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The ULINK USB-JTAG Adapter section displays information about the driver version, device family, and the ULINKpro firmware.

Target Driver Setup - ULINKpro Adapter

  • Serial No displays the ULINKpro identification number. When more ULINKpro adapters are connected, use the drop-down list to select the adapter.
  • Max JTAG Clock sets the highest JTAG clock rate used to communicate to the target board. ULINKpro supports the Return Clock (RTCK) pin, which is available on most ARM7 and ARM9 devices. The RTCK signal adjusts the JTAG clock speed to the highest possible rate for that device.
  • Use nTRST asserts the nTRST signal for JTAG reset. By default, this option is disabled.

Some applications require starting with a lower JTAG Clock from RESET and have to switch to higher clock rates when debugging. Use the VTREG DEBUG_CLOCK to alter the clock rate from scripts:

  The function sets the JTAG Debug Clock to 1MHz
  after the Main Clock has been enabled and selected.
FUNC void setJTAGClock()  {
  enableMainClock();         // add your code to switch on the Main Clock

  DEBUG_CLOCK = 1000000;     // Set JTAG Debug Clock to 1MHz

  enableMainPLL();           // add your code to enable the main PLL


  • RTCK can be used only with devices that provide the RTCK pin.
  • When communication issues arise, reduce the clock rate in Max JTAG Clock.
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