Cobham Gaisler is a world leader in embedded computer systems for harsh environments, with footprints in many parts of the solar system. We provide the full ecosystem to support digital hardware design for mission critical System-on-a-Chip solutions. The IP cores and development tools support processors based on the SPARC and RISC-V architectures. In addition to this, a number of standard components are available.


GRMON2 is a debug monitor for the LEON2, LEON3 and LEON4 Debug Support Unit (DSU), providing a non-intrusive debug environment on real target hardware. The LEON DSU can be controlled through any AMBA AHB master and GRMON2 therefore supports communication through a large number of interfaces.

GRMON2 has extended support for multi-core systems, such as the dual-core GR712RC Dual-Core LEON3FT Processor and GR740 Quad-Core LEON4FT Processor devices..

Basic features

  • Read/write access to all LEON registers and memory
  • Downloading and execution of LEON applications
  • Built-in disassembler and trace buffer management
  • Breakpoint and watchpoint management
  • Command-line mode
  • Remote connection to GNU debugger (GDB)
  • Single word or burst access to AMBA on-chip bus
  • GRLIB Plug & Play support
  • Auto-probing and initialisation of LEON peripherals and memory settings
  • Error injection for fault-tolerant LEON processors
  • Supported debug interfaces: PCI, USB, Ethernet, JTAG, UART and SpaceWire
  • Common Flash Interface (CFI) compatible Flash PROM programming

Advanced features 

  • Tcl interactive interpreter support
    • All commands have been rewritten to support Tcl syntax
    • TAB-completion on Tcl variables, procedures, namespaces etc.
    • Tcl scripting:
      • GRMON2 commands leave return values for scripting
      • Variables are exported that let the user access DSU and debug drivers without using commands
      • Start-up scripts
    • Extend GRMON2:
      • custom AMBA cores using new Tcl-driver interface
      • easy custom command implementation using Tcl
      • install custom handlers (hooks) on certain events
  • In-application help system with full command reference
  • Multi-core system support
  • GDB does not consume the console, i.e. it's possible to inspect registers etc. while GDB is connected
  • GDB watchpoint support
  • Translates virtual addresses for GDB, e.g. it's possible to debug the Linux kernel
  • Expanded register information listing


GRMON2 provides a terminal based user interface. It is not a GUI application.

Supported platforms and system requirements

GRMON2 is currently provided for platforms: Linux-x86, Windows XP SP3 and Windows 7.

Documentation and download

GRMON2 user manual is available on-line.

Professional and evaluation versions of GRMON2 for Linux and Windows can be obtained from the download page.