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Allocating Array Memory to SDRAM ADSP-21489 EZ-Kit

Question asked by epalaima on Nov 16, 2017
Latest reply on Nov 18, 2017 by pereira

Hi, I am writing a program using the ADSP-21489 Ez-Kit, which uses a large delay line array that is more than the on-chip memory can accommodate. I would like to allocate this array to the external SDRAM (MT48LC16M16A2P). In my research on the topic I have seen this done via pragma marks such as this:

“#pragma section (“seg_ext_dmda”)
int array1[100];”

I have also gathered that external memory needs to be configured in the app.ldf, which should be modified via the system.svc file. 


I have tried doing this, but whenever I check the use external memory option in the system.svc, my program (which is based on the ADSP-21469 Block Based Talkthru Example modified for the ADSP-21489) fails to pass audio to the output, even when no external memory is being allocated. 


I have heard that SIMD is possible from external memory on the ADSP-21489 processor. Is this true, and does this work with the run-time DSP library functions?


Can someone please provide an example as to how to correctly to external memory using the ADSP-21489 Ez-Kit?