NiosV Ashling GDB "Debugger disconnected, closed connection to 127.0.0.1 on port ..."

I got this message when trying to Run or Debug a NiosV from Ashling Eclipse tools.

Ashling GDB Server for RISC-V (ash-riscv-gdb-server).

v22.3.2, 19-Aug-2022, (c)Ashling Microsystems Ltd 2022.

Initializing connection ...

Checking for an active debug connection using the selected debug probe (SN: 1):

Cannot set the JTAG frequency, continuing with auto adjust mode

Connected to target device "" using USB-Blaster-2 (1) via JTAG at 15.00MHz.

Info : Active Harts Detected : 1

Info : [0] System architecture : RV32

Info : [0] Number of hardware breakpoints available : 1

Info : [0] Number of program buffers: 8

Info : [0] Number of data registers: 2

Info : [0] Memory Access -> Program buffer

Info : [0] Memory Access -> Abstract access memory

Info : [0] CSR & FP Register Access -> Abstract commands

Waiting for debugger connection on port 50991 for core 0.

Press 'Q' to Quit.

Got a debugger connection from 127.0.0.1 on port 50991.

[0x10000] Internal error. Abstract command execution failed: An abstract command is currently being executed.

Debugger disconnected, closed connection to 127.0.0.1 on port 50991.

Quitting (Ctrl + C)...

It turned out to be that the FPGA clock source to the NiosV debug port was lower than the JTAG_CLOCK frequency.

(Same problems would apply to JTAG UART and other things connected via the SLD TAP(SystemLevelDebug TestAccessPort))

Solutions:

- Increase Clock source in your FPGA design

- Lower JTAG_CLOCK speed on the PC