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Connect an audio source to J14, a speaker / headphone to J4 and check Path #1.
Connect an audio source to J13, a speaker / headphone to J5 and check Path #2.
The main idea is to create a Simulink environment that reads samples form 4 channels, process them and send them to 4 output channels. The example model is shown in Figure 14.
The Simulink driver block is based on the driver described in the previous chapters. Both drivers read and write samples using a double-buffering mechanism, but they differ in the way they activate the processing algorithm.
The algorithm code, in the Simulink environment, runs as a separate free-running task. At the start of the function it checks the semaphore to see if data is ready to read from the buffer – if not then it stays in a wait state until the semaphore is posted by the callback routine (Please refer to section ). Once this has been posted, it reads the data elements from the addresses supplied by the appropriate pointers. Once the algorithm has then processed the data, it writes the data elements from the addresses supplied by the appropriate pointers. After process is concluded, it will wait for the next frame of samples. This process then repeats until halted.
The callback function, in the Simulink environment, needs to set the appropriate pointers each time an EDMA interrupt occur, and post a semaphore for the “Algorithm” task afterwards.
The driver consists of 4 files:
The first three files are the same files used for the CCS driver. The ai24link.c file is similar to the user defined file (test.c for example) described in ,
This file contains the following functions and definitions:
Int16 r_data1[DATANUM*NUM_CODECS*BUFS_PER_CHANNEL]; // data buffer for readInt16 w_data1[DATANUM*NUM_CODECS*BUFS_PER_CHANNEL]; // data buffer for readInt16 r_data2[DATANUM*NUM_CODECS*BUFS_PER_CHANNEL]; // data buffer for writeInt16 w_data2[DATANUM*NUM_CODECS*BUFS_PER_CHANNEL]; // data buffer for write
Int16 *InSig1;
Int16 *InSig2;Int16 *InSig3;
Int16 *InSig4;Int16 *OutSig1;
Int16 *OutSig2;Int16 *OutSig3;
Int16 *OutSig4;
AIC24_Handle hAIC24;
SEM_Obj AIC24_ready_sem;
void AIC24LINK_init()
{// setting up the AIC24 handle
AIC24_InitDefaults(⩓hAIC24, NUM_CODECS, DATANUM, r_data1, r_data2, w_data1, w_data2, AIC24LINK_process);SEM_new(⩓AIC24_ready_sem,0);
}
void AIC24LINK_process(Int16 *r_data, Int16 *w_data)
{InSig1 = r_data;
InSig2 = r_data + DATANUM;InSig3 = r_data + DATANUM*2;
InSig4 = r_data + DATANUM*3;OutSig1 = w_data;
OutSig2 = w_data + DATANUM;OutSig3 = w_data + DATANUM*2;
OutSig4 = w_data + DATANUM*3;SEM_post(⩓AIC24_ready_sem);
}void AIC24LINK_wait()
{SEM_pend(⩓AIC24_ready_sem, SYS_FOREVER);
}
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