GRMON3 is a hardware monitor optimized for SPARC/LEON and RISC-V/NOEL-V systems, providing a non-intrusive debug environment.

GRMON3 has full support for multi-core systems, such as the GR740 Quad-Core LEON4 SPARC V8 Processor, the dual-core GR712RC and NOEL-V demonstration FPGA bitstreams.


-> Download GRMON3


A comprehensive debugger

The target system can be monitored and controlled by the graphical user interface with scripting support. A large number of debug link interfaces are supported and the debugger can be user-adapted for several system configurations.

- Read/write access to all LEON and NOEL-V registers and

- Execution control with support for multiple CPUs and OS threads

- Built-in disassembler and trace buffer management

- Breakpoint and watchpoint management

- Command-line mode

- Remote connection to GNU debugger (GDB)

- IDE support via the GDB connection,
see Software IDE quick-start guide (PDF)

- Auto-probing and initialization of LEON or NOEL-V peripherals
  and memory settings

- Error injection for fault-tolerant LEON processors

- Supported debug interfaces: USB, Ethernet, JTAG, UART and

- Common Flash Interface (CFI) compatible Flash PROM

- Tcl scripting support

- All GRMON commands are Tcl commands

- Custom commands and device drivers can be implemented
   by the user

- Hooks for installing custom handlers executed on certain

- Peripheral device register bits available as Tcl variables

- TAB-completion on Tcl variables, procedures, file names

- In-application help for all commands

- Context-based virtual memory handling

- Translates virtual addresses for GDB, e.g. it's possible to debug
  the VxWorks/Linux kernel








Graphical User Interface

The GRMON3 GUI greatly extends the traditional monitoring and control capabilities of GRMON:

- Debug-link and system configuration dialog

- Multi-core LEON/RISC-V and OS threads execution status and
  backtrace view

- Disassembly view with symbol and breakpoint information

- Breakpoints view for managing breakpoints and watchpoints

- Memory, CPU register and I/O register inspection and edit

- Optimized SPARC/LEON and RISC-V/NOEL-V IU register view

- C/C++ source level debugging including source code view,
  stepping and line breakpoints

- Variables and expressions views.

- Application launch dialog

- Tcl terminal views with history, tab-completion, etc.

- Application terminals via UART forwarding

- GRLIB SOC system hardware overview


Documentation and download

GRMON3 User's Manual is available on-line.

Professional and evaluation versions of GRMON3 for Linux and Windows can be obtained from the download page.



 Supported target devices

- All LEON/GRLIB systems (via PnP)

- LEON2, LEON3, LEON4, LEON5 SPARCv7/SPARCv8 systems

- NOEL-V 32-bit and 64-bit RISC-V based systems

- GR740, GR712RC

- UT699, UT699E and UT700

- GR716 Radiation-Tolerant Microcontroller

- GR718B Radiation-Tolerant 18x SpaceWire Router

- LEON2-based systems, including AT697, AT7913 (SPW-RTC) and AT7991 (AGGA-4)

Supported platforms and system requirements

GRMON3 is provided for platforms: Linux, Windows 7 and Windows 10.


The TSIM3 simulator and the GRMON3 debugger share a powerful scripting framework based on Tcl. Tcl scripts can adapt to minor differences in the respective Tcl environments so that the same script can be used in both TSIM3 and GRMON3. This enables users to easily transition from the simulation environment to real hardware validation, considerably reducing development time and improving overall productivity.