ADSP-21569 SigmaStudio and external memory usage for long delays

Question

Hi, 
 I'm working on a new design and we need to implement a new external delay custom algorithm in SigmaStudioForSHARC Rel4.5 for ADSP-21569. 
 Our goal is to create a delay block that allows up to 2-second delay at 96Khz and with the ability to instance at least 4x blocks on a single sigmastudio design. 
 I remember that for ADSP-214xx Analog provided an example for doing this in SigmaStudioForSharc rel 2.1 
 Unfortunately, both DSP and Software package are quite different and It's not possible to reuse the example in the newer DSP. 
 Is there a SigmaStudio external delay example for ADSP-215xx ? 
 In case we have to develop it from stretch the best way is to configure the SigmaStudio Target firmware to use all the external ram for SigmaStudio algorithms, 
 In this way, we can develop a generic Delay algorithm and the SS App will use the external or Internal RAM depending on the available space, 
 It is possible to use the external ram In this way? Thanks and Best regards

Sakthi^vel · Accepted Answer

Hi, 
 You can allocate delay buffer from the &ldquo;Memory requirement&rdquo; tab in Algorithm designer. The delay buffer can be allocated in State, StateB, StateC using &ldquo;Memory requirement&rdquo; tab. 
 State &ndash; Buffer will be allocated in L1 mem_block1_bw StateB &ndash; Buffer will be a llocated in L1 mem_block3_bw StateC &ndash; Buffer will be a llocated in L3 MY_SDRAM_DATA1_MEM if SDRAM is included in LDF file In case of no SDRAM inclusion in LDF file, StateC &ndash; Buffer will be a llocated in L2 mem_L2_bw_SS4G_Data 
 The value to be entered for required memory field is in words. 
 For example, 
 2 sec delay at 96K rate = 2*96K = 192000 words. (768000 bytes) 
 If you want to use external memory, stateC memory field can be used to reserve 192000 words for 2sec delay buffer. 
 The state pointer "pBlkAlgoInfo->pStateC" can be used as delay buffer that we reserved in the algorithm designer. 
 Thanks.)

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ADSP-21569 SigmaStudio and external memory usage for long delays