ARM Technical Support Knowledge Articles

R14 CORRUPTED DURING CLOCK INTERRUPT ON AT91RM9200

Applies to: RealView Real-Time Library

Answer


Information in this article applies to:


SYMPTOM

My program doesn't work properly because the value in R14 changes, during the RTX clock interrupt.

CAUSE

There is a possible hardware issue with some versions of the Atmel AT91RM9200 device.  When processing the following instruction, it does not update R14 (a.k.a. LR).

LDMDB SP,{SP,LR}^

which you can also write as:

LDMDB SP,{R13-R14}^

RESOLUTION

The attached update to the RL-ARM library contains a work-around for the hardware issue.  Download it, and replace the existing file in C:KeilARMRV30LIB

STATUS

Atmel is aware of this issue, and is researching it.


Article last edited on: 2006-11-15 07:32:35

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