ARM SUPPORTS ONLY TWO BREAKS IN FLASH ROM

Answer

Information in this article applies to:

ULINK USB-JTAG Adapter
ULINK2 USB-JTAG Adapter

QUESTION

I am debugging an application in Flash ROM. When I set more than two breakpoints I receive the following message.

This target device does not support all the defined breakpoints!
Please reduce the number of breakpoints and start again.

What is wrong? Is this a limitation of the Evaluation Version?

ANSWER

Breakpoints in Flash ROM are set using the Embedded ICE in the ARM CPU core. The Embedded ICE is a great help in debugging applications, but it has certain limitations. One of these is the number of breakpoints that you can define.

Since the Embedded ICE has several other shortcomings, we have focused on developing precise device simulation for ARM (see Advantages of µVision for ARM).

Note that there is no limitation in the number of breakpoints when you use RAM for program code during program debugging. However, RAM is limited on many hardware platforms.

Very few high-end emulators offer ways to re-program the Flash when the number of breakpoints is reached. This procedure is not only slow, but it has several limitations due missing peripheral synchronization.