ARM Technical Support Knowledge Articles

SINGLE STEP WITH ULINK JUMPS TO ADDRESS 20H

Applies to: C166 C Compiler

Answer


Information in this article applies to:


QUESTION

I am using ULINK to debug my application on an Infineon XC16x microcontroller. I download the application into off-chip RAM to be able to use an unlimited number of software breakpoints. Occasionally, I see that the program counter moves to address 0x000020 with a Step Into command. Continuing from this address makes no sense. What's going on?

ANSWER

This is a side effect of the branch prediction unit. ULINK uses the DEBUG instruction for software breakpoints in RAM. This DEBUG instruction is cached by the 'branch prediction unit' when CPUCON1.1 is set and the breakpoint was set on a JMP instruction.

In order to avoid this problem you can either turn off the branch prediction unit (CPUCON1.1) in your START_V2.A66 configuration file or you can use an updated UL2OCDS driver which is attached to this knowledgebase article. The attached ZIP file must be extracted into the KeilC166BIN folder. This updated driver is included in every C166 version newer than 5.05.

SEE ALSO

Article last edited on: 2005-06-15 08:26:39

Rate this article

[Bad]
|
|
[Good]
Disagree? Move your mouse over the bar and click

Did you find this article helpful? Yes No

How can we improve this article?

Link to this article
Copyright © 2011 ARM Limited. All rights reserved. External (Open), Non-Confidential