RL-ARM: R14 CORRUPTED DURING CLOCK INTERRUPT ON AT91RM9200

Information in this article applies to:

• RL-ARM All Versions

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:\Keil\ARM\RV30\LIB

STATUS

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

ATTACHED FILES

Request the files attached to this knowledgebase article.

Last Reviewed: Wednesday, November 15, 2006