The J-Link RDI software makes debugging ARM microcontrollers with built-in flash memory more powerful and convenient. Because increasing RAM size can get expensive, most ARM microcontrollers don’t have enough RAM to hold program and data in real-world applications. Debugging in flash memory is normally limited to the two hardware breakpoints permitted by the on-chip debug unit of ARM chips (ICE-breaker module).

The J-Link RDI software enables you to set an unlimited number of software breakpoints in flash memory areas rather than just the two hardware breakpoints. A RAM code, specially designed for this purpose, quickly sets and clears flash memory breakpoints. On microcontrollers with fast flash memory, the difference between breakpoints in RAM and flash memory is hardly noticeable. In addition, a combination of software and hardware breakpoints, as well as a built-in instruction set simulator, minimize the number of flash memory operations that need to be performed. This minimizes delays and maximizes the flash memory’s lifetime. All of the ARM microcontroller’s resources are available to the application program; no memory is lost for debugging.

The J-Link RDI software can be used with any RDI-compliant debugger (e.g., the IAR Embedded Workbench). J-Link is a small JTAG emulator designed for ARM cores; it connects via USB to the Windows PC host. J-Link supports any ARM7/9 core including Thumb mode; you can use it for debugging, flash memory programming, and communicating with the core via DLL (enables full access to JLink).

J-Mem, a small stand-alone application for Microsoft Windows 2000/XP, and the DLL are included in addition to a USB and 20-pin flat cable. J-Mem displays the memory content of ARM systems and enables the modification of RAM and special function registers (SFRs) while the target is running.

J-Link works efficiently and achieves download speeds of 150 kbps. Additional software packages (J-Flash, RDI software, and flash breakpoints) are available. The J-Link emulator costs approximately $315. The RDI software costs approximately $250.

SEGGER Microcontroller Systeme GmbH
www.segger.com