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ULINK: Memory Access Error while using ETM Trace on LPC4300


Information in this knowledgebase article applies to:

  • MDK-ARM Version 5.x
  • ULINK Pro Debug Adapter
  • Software Pack: Keil.LPC4300_DFP
  • ETM TRACE

QUESTION

I have copied an example from Pack Installer based on LPC4300 and made it compatible for ETM Trace as per the settings but as soon as debug session has been started, I see Cannot access Memory error messages in Command Window:

Cannot access Memory (@ 0x00000050, Read, Acc Size: 4 Byte)
Cannot access Memory (@ 0x00000052, Read, Acc Size: 2 Byte)
Cannot access Memory (@ 0x00000054, Read, Acc Size: 2 Byte)
Cannot access Memory (@ 0x00000056, Read, Acc Size: 2 Byte)
Cannot access Memory (@ 0x00000058, Read, Acc Size: 4 Byte)

ANSWER

The examples provided in Pack Installer are not compatible for ETM Trace and reason of this error is non-synchronization between System Clock and Trace Core Clock. To make these examples compatible for ETM Trace, the System Clock has to be reduced.

In your µVision project open system_LPC43xx.c, scroll down to section Configure PLL1 and change the settings as per below:

/* PLL1 output clock: 120MHz, Fcco: 240MHz, N = 1, M = 20, P = 1              */
#define PLL1_NSEL   0           /* Range [0 -   3]: Pre-divider ratio N       */
#define PLL1_MSEL  19           /* Range [0 - 255]: Feedback-divider ratio M  */
#define PLL1_PSEL   0           /* Range [0 -   3]: Post-divider ratio P      */

#define PLL1_BYPASS 0           /* 0: Use PLL, 1: PLL is bypassed             */
#define PLL1_DIRECT 0           /* 0: Use PSEL, 1: Don't use PSEL             */
#define PLL1_FBSEL  0           /* 0: FCCO is used as PLL feedback            */

MORE INFORMATION

SEE ALSO

Last Reviewed: Tuesday, April 4, 2017


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